diff --git a/CHANGES b/CHANGES
index e5be483e77..87a537c1e9 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,4 +1,8 @@
 
+2.0-851 | 2012-07-24 15:04:14 -0700
+
+  * New built-in function to_double(s: string). (Scott Campbell)
+    
 2.0-849 | 2012-07-24 11:06:16 -0700
 
   * Adding missing include needed on some systems. (Robin Sommer)
diff --git a/VERSION b/VERSION
index 3ccfd995f9..c4f46b78c9 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.0-849
+2.0-851
diff --git a/src/bro.bif b/src/bro.bif
index f18d3ba1b5..2c22626c99 100644
--- a/src/bro.bif
+++ b/src/bro.bif
@@ -2604,6 +2604,29 @@ function to_subnet%(sn: string%): subnet
 	return ret;
 	%}
 
+## Converts a :bro:type:`string` to a :bro:type:`double`.
+##
+## str: The :bro:type:`string` to convert.
+##
+## Returns: The :bro:type:`string` *str* as double, or 0 if *str* has
+##          an invalid format.
+##
+function to_double%(str: string%): double
+	%{
+	const char* s = str->CheckString();
+	char* end_s;
+	
+	double d = strtod(s, &end_s);
+	
+	if ( s[0] == '\0' || end_s[0] != '\0' )
+		{       
+		builtin_error("bad conversion to count", @ARG@[0]);
+		d = 0;
+		}     
+	
+	return new Val(d, TYPE_DOUBLE);
+	%}
+
 ## Converts a :bro:type:`count` to an :bro:type:`addr`.
 ##
 ## ip: The :bro:type:`count` to convert.
diff --git a/testing/btest/Baseline/bifs.to_double_from_string/error b/testing/btest/Baseline/bifs.to_double_from_string/error
new file mode 100644
index 0000000000..5ba5997101
--- /dev/null
+++ b/testing/btest/Baseline/bifs.to_double_from_string/error
@@ -0,0 +1,2 @@
+error in /da/home/robin/bro/master/testing/btest/.tmp/bifs.to_double_from_string/to_double_from_string.bro, line 7 and /da/home/robin/bro/master/testing/btest/.tmp/bifs.to_double_from_string/to_double_from_string.bro, line 15: bad conversion to count (to_double(d) and NotADouble)
+error in /da/home/robin/bro/master/testing/btest/.tmp/bifs.to_double_from_string/to_double_from_string.bro, line 7 and /da/home/robin/bro/master/testing/btest/.tmp/bifs.to_double_from_string/to_double_from_string.bro, line 16: bad conversion to count (to_double(d) and )
diff --git a/testing/btest/Baseline/bifs.to_double_from_string/output b/testing/btest/Baseline/bifs.to_double_from_string/output
new file mode 100644
index 0000000000..661d2b1479
--- /dev/null
+++ b/testing/btest/Baseline/bifs.to_double_from_string/output
@@ -0,0 +1,5 @@
+to_double(3.14) = 3.14 (SUCCESS)
+to_double(-3.14) = -3.14 (SUCCESS)
+to_double(0) = 0.0 (SUCCESS)
+to_double(NotADouble) = 0.0 (SUCCESS)
+to_double() = 0.0 (SUCCESS)
diff --git a/testing/btest/bifs/to_double_from_string.bro b/testing/btest/bifs/to_double_from_string.bro
new file mode 100644
index 0000000000..88af6758f0
--- /dev/null
+++ b/testing/btest/bifs/to_double_from_string.bro
@@ -0,0 +1,16 @@
+# @TEST-EXEC: bro -b %INPUT >output 2>error
+# @TEST-EXEC: btest-diff output
+# @TEST-EXEC: btest-diff error
+
+function test_to_double(d: string, expect: double)
+	{
+	local result = to_double(d);
+	print fmt("to_double(%s) = %s (%s)", d, result,
+	          result == expect ? "SUCCESS" : "FAILURE");
+	}
+
+test_to_double("3.14", 3.14);
+test_to_double("-3.14", -3.14);
+test_to_double("0", 0);
+test_to_double("NotADouble", 0);
+test_to_double("", 0);