diff --git a/src/OpenTelemetry.Exporter.Prometheus.HttpListener/Internal/PrometheusMetric.cs b/src/OpenTelemetry.Exporter.Prometheus.HttpListener/Internal/PrometheusMetric.cs
index df1632ca467..81d0a1da42a 100644
--- a/src/OpenTelemetry.Exporter.Prometheus.HttpListener/Internal/PrometheusMetric.cs
+++ b/src/OpenTelemetry.Exporter.Prometheus.HttpListener/Internal/PrometheusMetric.cs
@@ -119,6 +119,41 @@ static StringBuilder CreateStringBuilder(string name)
         }
     }
 
+    internal static string SanitizeUnitName(string unit)
+    {
+        if (string.IsNullOrEmpty(unit))
+        {
+            return string.Empty;
+        }
+
+        var sb = new StringBuilder(unit.Length);
+        var lastCharUnderscore = false;
+
+        for (var i = 0; i < unit.Length; i++)
+        {
+            var c = unit[i];
+
+            if (char.IsLetterOrDigit(c))
+            {
+                sb.Append(c);
+                lastCharUnderscore = false;
+            }
+            else if (!lastCharUnderscore && sb.Length > 0)
+            {
+                sb.Append('_');
+                lastCharUnderscore = true;
+            }
+        }
+
+        // Strip trailing underscore
+        if (sb.Length > 0 && sb[sb.Length - 1] == '_')
+        {
+            sb.Length--;
+        }
+
+        return sb.Length == 0 ? string.Empty : sb.ToString();
+    }
+
     internal static string RemoveAnnotations(string unit)
     {
         // UCUM standard says the curly braces shouldn't be nested:
@@ -208,6 +243,7 @@ private static string GetUnit(string unit)
             updatedUnit = MapUnit(updatedUnit.AsSpan());
         }
 
+        updatedUnit = SanitizeUnitName(updatedUnit);
         return updatedUnit;
     }
 
diff --git a/test/OpenTelemetry.Exporter.Prometheus.HttpListener.Tests/PrometheusMetricTests.cs b/test/OpenTelemetry.Exporter.Prometheus.HttpListener.Tests/PrometheusMetricTests.cs
index 5e8856f4843..1b3ef129b5f 100644
--- a/test/OpenTelemetry.Exporter.Prometheus.HttpListener.Tests/PrometheusMetricTests.cs
+++ b/test/OpenTelemetry.Exporter.Prometheus.HttpListener.Tests/PrometheusMetricTests.cs
@@ -263,6 +263,42 @@ public void GetPrometheusType_MapsOpenTelemetryMetricsTypeToPrometheus(MetricsMa
     [Fact]
     public void Name_EmptyUnit_NoSuffixAdded() => AssertName("metric", string.Empty, PrometheusType.Gauge, false, "metric");
 
+    [Fact]
+    public void Name_MalformedUnit_HashRU_Sanitized()
+        => AssertName("metric", "# RU", PrometheusType.Gauge, false, "metric_RU");
+
+    [Fact]
+    public void Name_MalformedUnit_HashOnly_Unitless()
+        => AssertName("metric", "#", PrometheusType.Gauge, false, "metric");
+
+    [Fact]
+    public void Name_MalformedUnit_HashSpaceHash_Unitless()
+        => AssertName("metric", "# #", PrometheusType.Gauge, false, "metric");
+
+    [Fact]
+    public void Name_MalformedUnit_HashUnderscoreRDotUDot_Sanitized()
+        => AssertName("metric", "#_R.U.", PrometheusType.Gauge, false, "metric_R_U");
+
+    [Fact]
+    public void SanitizeUnitName_Valid()
+        => Assert.Equal("bytes", PrometheusMetric.SanitizeUnitName("bytes"));
+
+    [Fact]
+    public void SanitizeUnitName_WithInvalidChars()
+        => Assert.Equal("RU", PrometheusMetric.SanitizeUnitName("# RU"));
+
+    [Fact]
+    public void SanitizeUnitName_OnlyInvalidChars_ReturnsEmpty()
+        => Assert.Equal(string.Empty, PrometheusMetric.SanitizeUnitName("#"));
+
+    [Fact]
+    public void SanitizeUnitName_Empty_ReturnsEmpty()
+        => Assert.Equal(string.Empty, PrometheusMetric.SanitizeUnitName(string.Empty));
+
+    [Fact]
+    public void SanitizeUnitName_DotsCollapsed()
+        => Assert.Equal("R_U", PrometheusMetric.SanitizeUnitName("R.U."));
+
     [Fact]
     public void Name_NullUnit_NoSuffixAdded()
     {
@@ -361,7 +397,7 @@ public void GetPrometheusType_HistogramVariants_ReturnsHistogram(int metricTypeV
 
     [Fact]
     public void Name_MultipleSlashesInUnit_FirstSlashProcessed()
-        => AssertName("metric", "req/s/extra", PrometheusType.Gauge, false, "metric_req_per_s/extra"); // // Multiple slashes
+        => AssertName("metric", "req/s/extra", PrometheusType.Gauge, false, "metric_req_per_s_extra"); // Multiple slashes
 
     [Theory]
     [InlineData(PrometheusType.Counter)]