diff --git a/src/error.rs b/src/error.rs
index d4fbb54..5b2241a 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -74,6 +74,9 @@ pub enum Error {
     #[cfg(feature = "functions")]
     #[allow(dead_code)]
     UserFunctionError(Box<error::Error + Send + Sync>),
+
+    /// Error available for the implementors of the `ToSql` trait.
+    ToSqlConversionFailure(Box<error::Error + Send + Sync>),
 }
 
 impl From<str::Utf8Error> for Error {
@@ -128,6 +131,7 @@ impl fmt::Display for Error {
             }
             #[cfg(feature = "functions")]
             Error::UserFunctionError(ref err) => err.fmt(f),
+            Error::ToSqlConversionFailure(ref err) => err.fmt(f),
         }
     }
 }
@@ -155,6 +159,7 @@ impl error::Error for Error {
             Error::InvalidFunctionParameterType(_, _) => "invalid function parameter type",
             #[cfg(feature = "functions")]
             Error::UserFunctionError(ref err) => err.description(),
+            Error::ToSqlConversionFailure(ref err) => err.description(),
         }
     }
 
@@ -181,6 +186,7 @@ impl error::Error for Error {
 
             #[cfg(feature = "functions")]
             Error::UserFunctionError(ref err) => Some(&**err),
+            Error::ToSqlConversionFailure(ref err) => Some(&**err),
         }
     }
 }