diff --git a/src/Constructorio_NET.Tests/client/modules/RecommendationsTests.cs b/src/Constructorio_NET.Tests/client/modules/RecommendationsTests.cs
index 99a7c9d..09b30e3 100644
--- a/src/Constructorio_NET.Tests/client/modules/RecommendationsTests.cs
+++ b/src/Constructorio_NET.Tests/client/modules/RecommendationsTests.cs
@@ -321,5 +321,53 @@ public async Task GetRecommendationsResultsShouldReturnAResultProvidedUserInfo()
             Assert.GreaterOrEqual(res.Response.Results.Count, 0, "Results exist");
             Assert.NotNull(res.ResultId, "Result id exists");
         }
+
+        [Test]
+        public async Task GetRecommendationsResultsWithPreFilterExpression()
+        {
+            ValuePreFilterExpression filterByBrand = new ValuePreFilterExpression("Brand", "XYZ");
+            RecommendationsRequest req = new RecommendationsRequest("filtered_items")
+            {
+                UserInfo = this.UserInfo,
+                PreFilterExpression = filterByBrand,
+            };
+            ConstructorIO constructorio = new ConstructorIO(this.Config);
+            RecommendationsResponse res = await constructorio.Recommendations.GetRecommendationsResults(req);
+
+            Assert.GreaterOrEqual(res.Response.Results.Count, 0, "Results exist");
+            Assert.NotNull(res.ResultId, "Result id exists");
+            Assert.IsNotNull(res.Request["pre_filter_expression"], "PreFilterExpression was passed as parameter");
+        }
+
+        [Test]
+        public async Task GetRecommendationsResultsWithPreFilterExpressionJson()
+        {
+            JObject preFilterExpressionJObject = JObject.Parse(
+                @"{
+                    'name': 'Brand',
+                    'value': 'XYZ'
+                }"
+            );
+            JsonPrefilterExpression preFilterExpression = new JsonPrefilterExpression(
+                preFilterExpressionJObject
+            );
+            RecommendationsRequest req = new RecommendationsRequest("filtered_items")
+            {
+                UserInfo = this.UserInfo,
+                PreFilterExpression = preFilterExpression,
+            };
+
+            ConstructorIO constructorio = new ConstructorIO(this.Config);
+            RecommendationsResponse res = await constructorio.Recommendations.GetRecommendationsResults(req);
+            res.Request.TryGetValue("pre_filter_expression", out object reqPreFilterExpression);
+
+            Assert.AreEqual(
+                reqPreFilterExpression,
+                JObject.Parse(preFilterExpression.GetExpression()),
+                "Pre Filter Expression is sent in request"
+            );
+            Assert.GreaterOrEqual(res.Response.Results.Count, 0, "Results exist");
+            Assert.NotNull(res.ResultId, "Result id exists");
+        }
     }
 }
diff --git a/src/Constructorio_NET.Tests/models/Recommendations/RecommendationsRequestTest.cs b/src/Constructorio_NET.Tests/models/Recommendations/RecommendationsRequestTest.cs
index 7f3f3a8..af55362 100644
--- a/src/Constructorio_NET.Tests/models/Recommendations/RecommendationsRequestTest.cs
+++ b/src/Constructorio_NET.Tests/models/Recommendations/RecommendationsRequestTest.cs
@@ -91,5 +91,26 @@ public void RecommendationsRequestWithInvalidPod()
         {
             Assert.Throws<ArgumentException>(() => new RecommendationsRequest(null));
         }
+
+        [Test]
+        public void GetRequestParametersWithPreFilterExpression()
+        {
+            ValuePreFilterExpression filterByGroupId = new ValuePreFilterExpression("group_id", "BrandXY");
+            ValuePreFilterExpression filterByColor = new ValuePreFilterExpression("Color", "red");
+            AndPreFilterExpression preFilterExpression = new AndPreFilterExpression(
+                new List<PreFilterExpression> { filterByGroupId, filterByColor }
+            );
+
+            RecommendationsRequest req = new RecommendationsRequest(this.Pod)
+            {
+                UserInfo = this.UserInfo,
+                PreFilterExpression = preFilterExpression
+            };
+
+            Hashtable requestParameters = req.GetRequestParameters();
+            Assert.IsNotNull(requestParameters[Constants.PRE_FILTER_EXPRESSION]);
+            Assert.IsTrue(requestParameters[Constants.PRE_FILTER_EXPRESSION].ToString().Contains("group_id"));
+            Assert.IsTrue(requestParameters[Constants.PRE_FILTER_EXPRESSION].ToString().Contains("BrandXY"));
+        }
     }
 }
diff --git a/src/constructor.io/models/Recommendations/RecommendationsRequest.cs b/src/constructor.io/models/Recommendations/RecommendationsRequest.cs
index 4871356..71eef29 100644
--- a/src/constructor.io/models/Recommendations/RecommendationsRequest.cs
+++ b/src/constructor.io/models/Recommendations/RecommendationsRequest.cs
@@ -75,6 +75,11 @@ public RecommendationsRequest(string podId)
         /// </summary>
         public VariationsMap VariationsMap { get; set; }
 
+        /// <summary>
+        /// Gets or sets the filtering expression used to scope recommendation results.
+        /// </summary>
+        public PreFilterExpression PreFilterExpression { get; set; }
+
         /// <summary>
         /// Get request parameters.
         /// </summary>
@@ -147,6 +152,12 @@ public Hashtable GetRequestParameters()
                 parameters.Add(Constants.VARIATIONS_MAP, serializedJson);
             }
 
+            if (this.PreFilterExpression != null)
+            {
+                string preFilterJson = this.PreFilterExpression.GetExpression();
+                parameters.Add(Constants.PRE_FILTER_EXPRESSION, preFilterJson);
+            }
+
             return parameters;
         }