diff --git a/ASCIIMathML.js b/ASCIIMathML.js
index 87607c6..3e05f56 100644
--- a/ASCIIMathML.js
+++ b/ASCIIMathML.js
@@ -451,6 +451,7 @@ var AMsymbols = [
 {input:"harr", tag:"mo", output:"\u2194", tex:"leftrightarrow", ttype:CONST},
 {input:"rArr", tag:"mo", output:"\u21D2", tex:"Rightarrow", ttype:CONST},
 {input:"lArr", tag:"mo", output:"\u21D0", tex:"Leftarrow", ttype:CONST},
+{input:"dArr", tag:"mo", output:"\u21D3", tex:"Downarrow", ttype:CONST},
 {input:"hArr", tag:"mo", output:"\u21D4", tex:"Leftrightarrow", ttype:CONST},
 //commands with argument
 {input:"sqrt", tag:"msqrt", output:"sqrt", tex:null, ttype:UNARY},
diff --git a/asciimath-based/ASCIIMath2TeX.php b/asciimath-based/ASCIIMath2TeX.php
index 0b755db..79d0da3 100644
--- a/asciimath-based/ASCIIMath2TeX.php
+++ b/asciimath-based/ASCIIMath2TeX.php
@@ -266,6 +266,7 @@ class AMtoTeX
 array( 'input'=>'harr', 'tex'=>'leftrightarrow'),
 array( 'input'=>'rArr', 'tex'=>'Rightarrow'),
 array( 'input'=>'lArr', 'tex'=>'Leftarrow'),
+array( 'input'=>'dArr', 'tex'=>'Downarrow'),
 array( 'input'=>'hArr', 'tex'=>'Leftrightarrow'),
 
 // Commands with argument
diff --git a/asciimath-based/ASCIIMathTeXImg.js b/asciimath-based/ASCIIMathTeXImg.js
index 7e79543..911dcc9 100644
--- a/asciimath-based/ASCIIMathTeXImg.js
+++ b/asciimath-based/ASCIIMathTeXImg.js
@@ -304,6 +304,7 @@ var AMsymbols = [
 {input:"harr", tag:"mo", output:"\u2194", tex:"leftrightarrow", ttype:CONST},
 {input:"rArr", tag:"mo", output:"\u21D2", tex:"Rightarrow", ttype:CONST},
 {input:"lArr", tag:"mo", output:"\u21D0", tex:"Leftarrow", ttype:CONST},
+{input:"dArr", tag:"mo", output:"\u21D3", tex:"Downarrow", ttype:CONST},
 {input:"hArr", tag:"mo", output:"\u21D4", tex:"Leftrightarrow", ttype:CONST},
 
 //commands with argument
diff --git a/mathjax/jax.js b/mathjax/jax.js
index 00a9e32..6b669f9 100644
--- a/mathjax/jax.js
+++ b/mathjax/jax.js
@@ -642,6 +642,7 @@ var AMsymbols = [
 {input:"harr", tag:"mo", output:"\u2194", tex:"leftrightarrow", ttype:CONST},
 {input:"rArr", tag:"mo", output:"\u21D2", tex:"Rightarrow", ttype:CONST},
 {input:"lArr", tag:"mo", output:"\u21D0", tex:"Leftarrow", ttype:CONST},
+{input:"dArr", tag:"mo", output:"\u21D3", tex:"Downarrow", ttype:CONST},
 {input:"hArr", tag:"mo", output:"\u21D4", tex:"Leftrightarrow", ttype:CONST},
 //commands with argument
 {input:"sqrt", tag:"msqrt", output:"sqrt", tex:null, ttype:UNARY},
diff --git a/test/unittests.js b/test/unittests.js
index 9adb80a..bf2082a 100644
--- a/test/unittests.js
+++ b/test/unittests.js
@@ -109,6 +109,7 @@ var unittests = [
 {input: "csch", output:"<mrow><mo>csch</mo><mo></mo></mrow>"},
 {input: "cup", output:"<mo>∪</mo>"},
 {input: "darr", output:"<mo>↓</mo>"},
+{input: "dArr", output:"<mo>⇓</mo>"},
 {input: "ddot", output:"<mover><mo></mo><mo>..</mo></mover>"},
 {input: "ddots", output:"<mo>⋱</mo>"},
 {input: "del", output:"<mo>∂</mo>"},