diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h
index 944b7f82d..f821690ef 100644
--- a/include/mbedtls/ecp.h
+++ b/include/mbedtls/ecp.h
@@ -36,6 +36,7 @@
 #define MBEDTLS_ERR_ECP_RANDOM_FAILED                     -0x4D00  /**< Generation of random value, such as (ephemeral) key, failed. */
 #define MBEDTLS_ERR_ECP_INVALID_KEY                       -0x4C80  /**< Invalid private or public key. */
 #define MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH                  -0x4C00  /**< Signature is valid but shorter than the user-supplied length. */
+#define MBEDTLS_ERR_ECP_IN_PROGRESS                       -0x4B80  /**< Operation in progress, try again with the same parameters. */
 
 #if !defined(MBEDTLS_ECP_ALT)
 /*
diff --git a/include/mbedtls/error.h b/include/mbedtls/error.h
index 31591e2d6..6c580676d 100644
--- a/include/mbedtls/error.h
+++ b/include/mbedtls/error.h
@@ -76,7 +76,7 @@
  * DHM       3   9
  * PK        3   14 (Started from top)
  * RSA       4   9
- * ECP       4   8 (Started from top)
+ * ECP       4   9 (Started from top)
  * MD        5   4
  * CIPHER    6   6
  * SSL       6   17 (Started from top)
diff --git a/library/error.c b/library/error.c
index db42381c4..5845303c7 100644
--- a/library/error.c
+++ b/library/error.c
@@ -225,6 +225,8 @@ void mbedtls_strerror( int ret, char *buf, size_t buflen )
             mbedtls_snprintf( buf, buflen, "ECP - Invalid private or public key" );
         if( use_ret == -(MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH) )
             mbedtls_snprintf( buf, buflen, "ECP - Signature is valid but shorter than the user-supplied length" );
+        if( use_ret == -(MBEDTLS_ERR_ECP_IN_PROGRESS) )
+            mbedtls_snprintf( buf, buflen, "ECP - Operation in progress, try again with the same parameters" );
 #endif /* MBEDTLS_ECP_C */
 
 #if defined(MBEDTLS_MD_C)