diff --git a/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.OSX.cs b/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.OSX.cs
index 849306016b3935..07f55780d82de9 100644
--- a/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.OSX.cs
+++ b/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.OSX.cs
@@ -117,8 +117,8 @@ private static TimeSpan MapTime(ulong sysTime)
             if (denom == default)
             {
                 Interop.libSystem.mach_timebase_info_data_t timeBase = GetTimeBase();
-                s_timeBase_denom = denom = timeBase.denom;
                 s_timeBase_numer = timeBase.numer;
+                s_timeBase_denom = denom = timeBase.denom;
             }
             uint numer = s_timeBase_numer;