diff -u b/misc/ajax_facets.js b/misc/ajax_facets.js
--- b/misc/ajax_facets.js
+++ b/misc/ajax_facets.js
@@ -514,6 +514,10 @@
       query.pages = Drupal.ajax_facets.queryState.pages;
     }
 
+    // Respect existing query parameters in url.
+    // Merge respected parameters with facet parameters recursively without duplicates.
+    $.extend(true, query, Drupal.ajax_facets.simplifyObject(Drupal.ajax_facets.getAdditionalQueryParameters()));
+
     // Add query string to base url.
     if (!$.isEmptyObject(query)) {
       baseUrl += '?' + decodeURIComponent($.param(query));
@@ -523,6 +527,52 @@
   };
 
   /**
+   * Returns additional (not facet) query parameters from current url.
+   */
+  Drupal.ajax_facets.getAdditionalQueryParameters = function() {
+    var result = {};
+
+    if (window.location.href.indexOf('?') != -1) {
+      var respectedParameters = window.location.href.split('?')[1].split('&');
+
+      // Get all query parameters in array.
+      for (var i = 0; i < respectedParameters.length; i++) {
+        var pair = respectedParameters[i].split('=');
+
+        // Remove brackets from multiple parameter.
+        pair[0] = pair[0].replace('[]', '');
+
+        // We interested only in additional parameters but not in facet parameters.
+        if (pair[0] != 'f') {
+          if (!result[pair[0]]) {
+            result[pair[0]] = [];
+            result[pair[0]].push(pair[1]);
+          } else {
+            result[pair[0]].push(pair[1]);
+          }
+        }
+      }
+    }
+
+    return result;
+  };
+
+  /**
+   * Returns simplified object.
+   *
+   * If object has array property with only one element then that array will be turn into simple value instead of array.
+   */
+  Drupal.ajax_facets.simplifyObject = function(obj) {
+    for (var name in obj) {
+      if (obj[name].length === 1) {
+        obj[name] = obj[name][0];
+      }
+    }
+
+    return obj;
+  };
+
+  /**
    * Initialize the history state. We only want to do this on the initial page
    * load but we can't call it until after a facet has been clicked because we
    * need to communicate which one is being "deactivated" for our ajax success