diff --git a/src/c/numbers/log.d b/src/c/numbers/log.d
index dd1e0ec95..68e939a3b 100644
--- a/src/c/numbers/log.d
+++ b/src/c/numbers/log.d
@@ -17,6 +17,7 @@
 #include <ecl/ecl.h>
 #include <ecl/internal.h>
 #include <complex.h>
+#include <float.h>
 #include <ecl/impl/math_dispatch.h>
 
 #pragma STDC FENV_ACCESS ON
@@ -88,6 +89,22 @@ ecl_log1_simple(cl_object x)
   return ecl_make_single_float(logf(ecl_to_float(x)));
 }
 
+static cl_object
+ecl_log1_ratio(cl_object x)
+{
+  cl_object num = x->ratio.num;
+  cl_object den = x->ratio.den;
+  cl_index lnum = ecl_integer_length(num);
+  cl_index lden = ecl_integer_length(den);
+  if ((lnum > lden) ? (lnum - lden >= FLT_MAX_EXP) : (lden - lnum >= -FLT_MIN_EXP)) {
+    cl_object numlog = ecl_log1(num);
+    cl_object denlog = ecl_log1(den);
+    return ecl_minus(numlog, denlog);
+  } else {
+    return ecl_log1_simple(x);
+  }
+}
+
 static cl_object
 ecl_log1_single_float(cl_object x)
 {
@@ -182,7 +199,7 @@ ecl_log1_clfloat(cl_object x)
 #endif
 
 MATH_DEF_DISPATCH1(log1, @[log], @[number],
-                   ecl_log1_simple, ecl_log1_bignum, ecl_log1_simple,
+                   ecl_log1_simple, ecl_log1_bignum, ecl_log1_ratio,
                    ecl_log1_single_float, ecl_log1_double_float, ecl_log1_long_float,
                    ecl_log1_complex,
                    ecl_log1_csfloat, ecl_log1_cdfloat, ecl_log1_clfloat);
diff --git a/src/h/impl/math_dispatch.h b/src/h/impl/math_dispatch.h
index 6acf3cffe..23f900206 100644
--- a/src/h/impl/math_dispatch.h
+++ b/src/h/impl/math_dispatch.h
@@ -54,6 +54,7 @@ typedef cl_object (*math_one_arg_fn)(cl_object);
         }                                                               \
         return name##dispatch[t](arg);                                  \
     }
+
 #define MATH_DEF_DISPATCH1(name,id,type,fix,big,ratio,                  \
                            single_float,double_float,long_float,        \
                            complex,csfloat,cdfloat,clfloat)             \
diff --git a/src/tests/normal-tests/mixed.lsp b/src/tests/normal-tests/mixed.lsp
index 0d7522e39..c3f82c51b 100644
--- a/src/tests/normal-tests/mixed.lsp
+++ b/src/tests/normal-tests/mixed.lsp
@@ -429,3 +429,8 @@
   (let ((vector (si:make-vector t 10 t nil nil nil)))
     (si:adjust-vector vector 20)
     (is (= 20 (array-total-size vector)))))
+
+;;; Created: 2022-11-10
+;;; Contains: a test for a logarithm of a very small ratio
+(test mix.0023.log-small-ratio
+  (finishes (log (/ 1 6319748715279270675921934218987893281199411530039296))))