diff --git a/cypress/e2e/origin-search.cy.js b/cypress/e2e/origin-search.cy.js
--- a/cypress/e2e/origin-search.cy.js
+++ b/cypress/e2e/origin-search.cy.js
@@ -1,5 +1,5 @@
 /**
- * Copyright (C) 2019-2021  The Software Heritage developers
+ * Copyright (C) 2019-2022  The Software Heritage developers
  * See the AUTHORS file at the top-level directory of this distribution
  * License: GNU Affero General Public License version 3, or any later version
  * See top-level LICENSE file for more information
@@ -311,6 +311,30 @@
     }
   });
 
+  it('should encode origin argument in latest visit URL queried by XHR', function() {
+    // origin added in tests data by Python
+    const originUrl = 'https://example.org/project/download.php?version=2.0';
+    cy.intercept(`**/api/1/origin/${encodeURIComponent(originUrl)}/visit/latest/**`)
+      .as('checkOriginVisit');
+
+    doSearch(originUrl);
+
+    cy.wait('@checkOriginVisit');
+
+    cy.get('.swh-search-result-entry')
+            .should('have.length', 1);
+
+    cy.get('.swh-search-result-entry#origin-0 .swh-origin-visit-type')
+            .should('have.text', 'tar');
+
+    cy.get('.swh-search-result-entry#origin-0 td a')
+            .should('have.text', originUrl);
+
+    cy.get('.swh-search-result-entry#origin-0 .swh-visit-status')
+      .should('have.text', 'Archived');
+
+  });
+
   context('Test pagination', function() {
     it('should not paginate if there are not many results', function() {
       // Setup search
diff --git a/swh/web/browse/assets/browse/origin-search.js b/swh/web/browse/assets/browse/origin-search.js
--- a/swh/web/browse/assets/browse/origin-search.js
+++ b/swh/web/browse/assets/browse/origin-search.js
@@ -1,11 +1,11 @@
 /**
- * Copyright (C) 2018-2021  The Software Heritage developers
+ * Copyright (C) 2018-2022  The Software Heritage developers
  * See the AUTHORS file at the top-level directory of this distribution
  * License: GNU Affero General Public License version 3, or any later version
  * See top-level LICENSE file for more information
  */
 
-import {handleFetchError, errorMessageFromResponse, isArchivedOrigin} from 'utils/functions';
+import {errorMessageFromResponse, handleFetchError, isArchivedOrigin} from 'utils/functions';
 
 const limit = 100;
 const linksPrev = [];
@@ -53,7 +53,7 @@
       tableRow += '</tr>';
       table.append(tableRow);
       // get async latest visit snapshot and update visit status icon
-      let latestSnapshotUrl = Urls.api_1_origin_visit_latest(origin.url);
+      let latestSnapshotUrl = Urls.api_1_origin_visit_latest(encodeURIComponent(origin.url));
       latestSnapshotUrl += '?require_snapshot=true';
       promises.push(fetch(latestSnapshotUrl));
     }
diff --git a/swh/web/tests/data.py b/swh/web/tests/data.py
--- a/swh/web/tests/data.py
+++ b/swh/web/tests/data.py
@@ -270,6 +270,15 @@
             visit_type="tar",
         )
 
+    # origin used in cypress test for origins search
+    _add_origin(
+        storage,
+        search,
+        counters,
+        origin_url="https://example.org/project/download.php?version=2.0",
+        visit_type="tar",
+    )
+
     sha1s: Set[Sha1] = set()
     directories = set()
     revisions = set()