diff --git a/display.c b/display.c
index 8f593c7..f89aeb9 100644
--- a/display.c
+++ b/display.c
@@ -133,6 +133,8 @@ void initCurses(void)
     init_pair(3, COLOR_BLUE, -1);  /* extended chars */
   }
   init_pair(4, COLOR_BLUE, COLOR_YELLOW); /* current cursor position*/
+  init_pair(5, COLOR_WHITE, COLOR_RED); /* color for marking different bytes */
+
 #endif
 
   initDisplay();
@@ -169,6 +171,8 @@ void initDisplay(void)
   }
   colsUsed = computeLineSize();
   buffer = realloc(buffer,page);
+  if(difffileName && *difffileName!='\0')
+    diffBuffer = malloc(page);
   bufferAttr = realloc(bufferAttr,page * sizeof(*bufferAttr));
 }
 
@@ -207,26 +211,35 @@ void display(void)
   if (MAX(fileSize, lastEditedLoc)) printw("/0x%llX", getfilesize());
   if (mode == bySector) printw("--sector %lld", (base + cursor) / SECTOR_SIZE);
 
+  if (difffileName && *difffileName != '\0')
+  printw("   DIFF: 0x%02X - 0x%02X <- %s ", buffer[cursor], diffBuffer[cursor], difffileName);
   move(cursor / lineLength, computeCursorXCurrentPos());
 }
 
 void displayLine(int offset, int max)
 {
-  int i,mark_color=0;
+  int i,mark_color=0,diff_color=0;
+  bool differs = FALSE;
 #ifdef HAVE_COLORS
   mark_color = COLOR_PAIR(4) | A_BOLD;
+  diff_color = COLOR_PAIR(5) | A_BOLD;
+
 #endif
   PRINTW(("%08lX   ", (int) (base + offset)));
   for (i = offset; i < offset + lineLength; i++) {
     if (i > offset) MAXATTRPRINTW(bufferAttr[i] & MARKED, (((i - offset) % blocSize) ? " " : "  "));
     if (i < max) {
+      differs = difffileName && *difffileName != '\0' && buffer[i] != diffBuffer[i];
       ATTRPRINTW(
 #ifdef HAVE_COLORS
 		 (!colored ? 0 :
       (cursor == i && hexOrAscii == 0 ? mark_color :
+
+      (differs ? diff_color :
 		  buffer[i] == 0 ? COLOR_PAIR(1) :
 		  buffer[i] < ' ' ? COLOR_PAIR(2) : 
-		  buffer[i] >= 127 ? COLOR_PAIR(3) : 0)
+		  buffer[i] >= 127 ? COLOR_PAIR(3) : 0))
+
       ) |
 #endif
 		 bufferAttr[i], ("%02X", buffer[i]));
@@ -235,9 +248,10 @@ void displayLine(int offset, int max)
   }
   PRINTW(("  "));
   for (i = offset; i < offset + lineLength; i++) {
+    differs = difffileName && *difffileName != '\0' && buffer[i] != diffBuffer[i];
     if (i >= max) PRINTW((" "));
-    else if (buffer[i] >= ' ' && buffer[i] < 127) ATTRPRINTW((cursor == i && hexOrAscii==1 ? mark_color : 0) | bufferAttr[i], ("%c", buffer[i]));
-    else ATTRPRINTW((cursor == i && hexOrAscii == 1 ? mark_color : 0) | bufferAttr[i], ("."));
+    else if (buffer[i] >= ' ' && buffer[i] < 127) ATTRPRINTW((cursor == i && hexOrAscii==1 ? mark_color : differs ? diff_color : 0) | bufferAttr[i], ("%c", buffer[i]));
+    else ATTRPRINTW((cursor == i && hexOrAscii == 1 ? mark_color : differs ? diff_color : 0) | bufferAttr[i], ("."));
   }
 }
 
diff --git a/file.c b/file.c
index b14fa4f..7cd1696 100644
--- a/file.c
+++ b/file.c
@@ -55,6 +55,38 @@ void openFile(void)
   biggestLoc = fileSize;
 }
 
+void openDiffFile(void) {
+  struct stat st;
+
+  if (!is_file(difffileName)) {
+    fprintf(stderr, "%s: %s: Not a file.\n", progName, difffileName);
+    exit(1);
+  }
+
+  if ((difffd = open(difffileName, O_RDONLY)) == -1) {
+    if (page)
+      exitCurses();
+    if (difffileName[0] == '-')
+      DIE(usage);
+    fprintf(stderr, "%s: ", progName);
+    perror(difffileName);
+    exit(1);
+  }
+
+  if (fstat(difffd, &st) != -1 && st.st_size > 0)
+    diffFileSize = st.st_size;
+  else {
+#ifdef BLKGETSIZE
+    unsigned long i;
+    if (ioctl(difffd, BLKGETSIZE, &i) == 0)
+      diffFileSize = (INT)i * 512;
+    else
+#endif
+      diffFileSize = 0;
+  }
+}
+
+
 void readFile(void)
 {
   typePage *p;
@@ -82,7 +114,18 @@ void readFile(void)
     }
   }
   if (mark_set) markSelectedRegion();
+  if(difffileName && *difffileName != '\0')
+    readDiffFile();
+}
+
+void readDiffFile(void) {
+  typePage *p;
+  INT i;
+
+  memset(diffBuffer, 0, page * sizeof(*diffBuffer));
 
+  LSEEK(difffd, base);
+  diffnbBytes = read(difffd, diffBuffer, page);
 }
 
 int findFile(void)
diff --git a/hexedit.c b/hexedit.c
index 0f634e7..f391e25 100644
--- a/hexedit.c
+++ b/hexedit.c
@@ -29,6 +29,13 @@ int isReadOnly, fd, nbBytes, oldcursor, oldattr, oldcursorOffset;
 int sizeCopyBuffer, *bufferAttr;
 char *progName, *fileName, *baseName;
 unsigned char *buffer, *copyBuffer;
+
+unsigned char *diffBuffer;
+char *difffileName;
+INT diffFileSize;
+int difffd, diffnbBytes;
+
+
 typePage *edited;
 
 char *lastFindFile = NULL, *lastYankToAFile = NULL, *lastAskHexString = NULL, *lastAskAsciiString = NULL, *lastFillWithStringHexa = NULL, *lastFillWithStringAscii = NULL;
@@ -45,7 +52,8 @@ const char * const usage = "usage: %s [-s | --sector] [-m | --maximize] [-l<n> |
 #ifdef HAVE_COLORS 
      " [--color]"
 #endif 
-     " [-h | --help] filename\n";
+     " [-h | --help] filename[ diffWithFile]\n"
+    "If you want mark differences between two files specify diffWithFile - only with --color\n";
 
 
 /*******************************************************************************/
@@ -56,7 +64,7 @@ int main(int argc, char **argv)
   progName = basename(argv[0]);
   argv++; argc--;
 
-  for (; argc > 0; argv++, argc--) 
+  for (; argc > 0; argv++, argc--)
     {
       if (streq(*argv, "-s") || streq(*argv, "--sector"))
 	mode = bySector;
@@ -83,13 +91,17 @@ int main(int argc, char **argv)
 	DIE(usage)
       else break;
     }
-  if (argc > 1) DIE(usage);
+  if (argc < 1) DIE(usage);
 
   init();
-  if (argc == 1) {
-    fileName = strdup(*argv);
-    openFile();
+  fileName = strdup(*argv);
+  argv++; argc--;
+  openFile();
+  if(argc == 1){
+    difffileName = strdup(*argv);
+    openDiffFile();
   }
+
   initCurses();
   if (fileName == NULL) {
     if (!findFile()) {
diff --git a/hexedit.h b/hexedit.h
index fc57aa9..a397a05 100644
--- a/hexedit.h
+++ b/hexedit.h
@@ -1,12 +1,14 @@
 #ifndef HEXEDIT_H
 #define HEXEDIT_H
 
+
 #include "config.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <getopt.h>
 #if HAVE_FCNTL_H
 #include <fcntl.h>
 #endif
@@ -100,6 +102,11 @@ extern int isReadOnly, fd, nbBytes, oldcursor, oldattr, oldcursorOffset;
 extern int sizeCopyBuffer, *bufferAttr;
 extern char *progName, *fileName, *baseName;
 extern unsigned char *buffer, *copyBuffer;
+extern INT diffFileSize;
+extern unsigned char *diffBuffer;
+extern char *difffileName;
+extern int difffd, diffnbBytes;
+
 extern typePage *edited;
 
 extern char *lastFindFile, *lastYankToAFile, *lastAskHexString, *lastAskAsciiString, *lastFillWithStringHexa, *lastFillWithStringAscii;
@@ -115,6 +122,8 @@ void quit(void);
 int tryloc(INT loc);
 void openFile(void);
 void readFile(void);
+void openDiffFile(void);
+void readDiffFile(void);
 int findFile(void);
 int computeLineSize(void);
 int computeCursorXCurrentPos(void);