diff --git a/py/modmath.c b/py/modmath.c
index 1071323..d5d135f 100644
--- a/py/modmath.c
+++ b/py/modmath.c
@@ -168,6 +168,8 @@
         mp_float_t base = mp_obj_get_float(args[1]);
         if (base <= (mp_float_t)0.0) {
             math_error();
+        } else if (base == (mp_float_t)1.0) {
+            mp_raise_msg(&mp_type_ZeroDivisionError, "division by zero");
         }
         return mp_obj_new_float(l / MICROPY_FLOAT_C_FUN(log)(base));
     }