diff --git a/reactos/lib/sdk/crt/crt.rbuild b/reactos/lib/sdk/crt/crt.rbuild
index b763d97727e..c33cb823b31 100644
--- a/reactos/lib/sdk/crt/crt.rbuild
+++ b/reactos/lib/sdk/crt/crt.rbuild
@@ -162,6 +162,7 @@
 		</if>
 		<if property="ARCH" value="amd64">
 			<file>cos.c</file>
+			<file>sin.c</file>
 			<directory name="amd64">
 				<file>alldiv.S</file>
 				<file>atan.S</file>
@@ -178,7 +179,6 @@
 				<file>log.S</file>
 				<file>log10.S</file>
 				<file>pow.S</file>
-				<file>sin.S</file>
 				<file>sqrt.S</file>
 				<file>sqrtf.S</file>
 				<file>tan.S</file>
diff --git a/reactos/lib/sdk/crt/libcntpr.rbuild b/reactos/lib/sdk/crt/libcntpr.rbuild
index deb0db03718..2ef42f05913 100644
--- a/reactos/lib/sdk/crt/libcntpr.rbuild
+++ b/reactos/lib/sdk/crt/libcntpr.rbuild
@@ -72,7 +72,6 @@
 				<file>log.S</file>
 				<file>log10.S</file>
 				<file>pow.S</file>
-				<file>sin.S</file>
 				<file>sqrt.S</file>
 				<file>tan.S</file>
 			</directory>
diff --git a/reactos/lib/sdk/crt/math/amd64/sin.S b/reactos/lib/sdk/crt/math/amd64/sin.S
deleted file mode 100644
index 683eedcd647..00000000000
--- a/reactos/lib/sdk/crt/math/amd64/sin.S
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * COPYRIGHT:         See COPYING in the top level directory
- * PROJECT:           ReactOS system libraries
- * PURPOSE:           Implementation of sin
- * FILE:              lib/sdk/crt/math/amd64/sin.S
- * PROGRAMMER:        Timo Kreuzer (timo.kreuzer@reactos.org)
- */
-
-/* INCLUDES ******************************************************************/
-
-#include <ndk/amd64/asm.h>
-#include <ndk/amd64/asmmacro.S>
-
-.intel_syntax noprefix
-
-
-.proc sin
-    UNIMPLEMENTED sin
-    ret
-
-.endproc
diff --git a/reactos/lib/sdk/crt/math/sin.c b/reactos/lib/sdk/crt/math/sin.c
new file mode 100644
index 00000000000..de99d50ee74
--- /dev/null
+++ b/reactos/lib/sdk/crt/math/sin.c
@@ -0,0 +1,89 @@
+/*
+ * COPYRIGHT:        See COPYING in the top level directory
+ * PROJECT:          ReactOS CRT
+ * FILE:             lib/crt/math/sin.c
+ * PURPOSE:          Generic C Implementation of sin
+ * PROGRAMMER:       Timo Kreuzer (timo.kreuzer@reactos.org)
+ */
+
+#define PRECISION 9
+#define M_PI 3.141592653589793238462643
+
+static double sin_off_tbl[] = {0.0, -M_PI/2., 0, -M_PI/2.};
+static double sin_sign_tbl[] = {1,-1,-1,1};
+
+double
+sin(double x)
+{
+    int quadrant;
+    double x2, result;
+
+    /* Calculate the quadrant */
+    quadrant = x * (2./M_PI);
+
+    /* Get offset inside quadrant */
+    x = x - quadrant * (M_PI/2.);
+
+    /* Normalize quadrant to [0..3] */
+    quadrant = (quadrant - 1) & 0x3;
+
+    /* Fixup value for the generic function */
+    x += sin_off_tbl[quadrant];
+
+    /* Calculate the negative of the square of x */
+    x2 = - (x * x);
+
+    /* This is an unrolled taylor series using <PRECISION> iterations 
+     * Example with 4 iterations:
+     * result = 1 - x^2/2! + x^4/4! - x^6/6! + x^8/8!
+     * To save multiplications and to keep the precision high, it's performed
+     * like this:
+     * result = 1 - x^2 * (1/2! - x^2 * (1/4! - x^2 * (1/6! - x^2 * (1/8!))))
+     */
+
+    /* Start with 0, compiler will optimize this away */
+    result = 0;
+
+#if (PRECISION >= 10)
+    result += 1./(1.*2*3*4*5*6*7*8*9*10*11*12*13*14*15*16*17*18*20);
+    result *= x2;
+#endif
+#if (PRECISION >= 9)
+    result += 1./(1.*2*3*4*5*6*7*8*9*10*11*12*13*14*15*16*17*18);
+    result *= x2;
+#endif
+#if (PRECISION >= 8)
+    result += 1./(1.*2*3*4*5*6*7*8*9*10*11*12*13*14*15*16);
+    result *= x2;
+#endif
+#if (PRECISION >= 7)
+    result += 1./(1.*2*3*4*5*6*7*8*9*10*11*12*13*14);
+    result *= x2;
+#endif
+#if (PRECISION >= 6)
+    result += 1./(1.*2*3*4*5*6*7*8*9*10*11*12);
+    result *= x2;
+#endif
+#if (PRECISION >= 5)
+    result += 1./(1.*2*3*4*5*6*7*8*9*10);
+    result *= x2;
+#endif
+    result += 1./(1.*2*3*4*5*6*7*8);
+    result *= x2;
+
+    result += 1./(1.*2*3*4*5*6);
+    result *= x2;
+
+    result += 1./(1.*2*3*4);
+    result *= x2;
+
+    result += 1./(1.*2);
+    result *= x2;
+
+    result += 1;
+
+    /* Apply correct sign */
+    result *= sin_sign_tbl[quadrant];
+
+    return result;
+}