diff --git a/.github/workflows/jsroot-ci.yml b/.github/workflows/jsroot-ci.yml
index d968e4969..c6f68b19a 100644
--- a/.github/workflows/jsroot-ci.yml
+++ b/.github/workflows/jsroot-ci.yml
@@ -67,6 +67,7 @@ jobs:
           node demo/node/file_proxy.js buffer ./hsimple.root
           node demo/node/rntuple_buffer_test.js
           node demo/node/rntuple_test.js demo/node/rntuple_test.root
+          node demo/node/rntuple_bitset_test.js demo/node/rntuple_bitset_test.root
           node demo/node/tree_int64_test.js demo/node/tree_int64_test.root
           node demo/node/tree_draw_range.js demo/node/rntuple_test.root
           node demo/node/rntuple_test32.js demo/node/rntuple_test32.root demo/node/rntuple_test32.json
@@ -187,6 +188,7 @@ jobs:
           node demo/node/file_proxy.js buffer ./hsimple.root
           node demo/node/rntuple_buffer_test.js
           node demo/node/rntuple_test.js demo/node/rntuple_test.root
+          node demo/node/rntuple_bitset_test.js demo/node/rntuple_bitset_test.root
           node demo/node/tree_int64_test.js demo/node/tree_int64_test.root
           node demo/node/tree_draw_range.js demo/node/rntuple_test.root
           node demo/node/rntuple_test32.js demo/node/rntuple_test32.root demo/node/rntuple_test32.json
@@ -242,6 +244,7 @@ jobs:
           node demo/node/file_proxy.js buffer ./hsimple.root
           node demo/node/rntuple_buffer_test.js
           node demo/node/rntuple_test.js demo/node/rntuple_test.root
+          node demo/node/rntuple_bitset_test.js demo/node/rntuple_bitset_test.root
           node demo/node/tree_int64_test.js demo/node/tree_int64_test.root
           node demo/node/tree_draw_range.js demo/node/rntuple_test.root
           node demo/node/rntuple_test32.js demo/node/rntuple_test32.root demo/node/rntuple_test32.json
diff --git a/demo/node/rntuple_bitset_test.cxx b/demo/node/rntuple_bitset_test.cxx
new file mode 100644
index 000000000..d1a47e7db
--- /dev/null
+++ b/demo/node/rntuple_bitset_test.cxx
@@ -0,0 +1,30 @@
+// macro to create rntuple_bitset_test.root used by rntuple_bitset_test.js
+// root -l -b -q rntuple_bitset_test.cxx
+
+#include <ROOT/RNTupleModel.hxx>
+#include <ROOT/RNTupleWriter.hxx>
+
+#include <bitset>
+
+void rntuple_bitset_test()
+{
+   auto model = ROOT::RNTupleModel::Create();
+
+   auto Bitset32 = model->MakeField<std::bitset<32>>("Bitset32");
+   auto Bitset48 = model->MakeField<std::bitset<48>>("Bitset48");
+
+   auto writer = ROOT::RNTupleWriter::Recreate(std::move(model), "Data", "rntuple_bitset_test.root");
+
+   for (int i = 0; i < 10; i++) {
+      Bitset32->reset();
+      Bitset32->set(i);
+      Bitset32->set(31 - i);
+
+      Bitset48->reset();
+      Bitset48->set(i);
+      Bitset48->set(30 + i);
+      Bitset48->set(47);
+
+      writer->Fill();
+   }
+}
diff --git a/demo/node/rntuple_bitset_test.js b/demo/node/rntuple_bitset_test.js
new file mode 100644
index 000000000..e00dcc61c
--- /dev/null
+++ b/demo/node/rntuple_bitset_test.js
@@ -0,0 +1,50 @@
+import { version, openFile, TSelector } from 'jsroot';
+import { rntupleProcess } from 'jsroot/rntuple';
+
+// check reading of std::bitset fields with more than 31 bits, file created with rntuple_bitset_test.cxx
+
+console.log(`JSROOT version ${version}`);
+
+let filename = './rntuple_bitset_test.root',
+    any_error = false;
+
+if (process?.argv && process.argv[2])
+   filename = process.argv[2];
+
+const file = await openFile(filename),
+      rntuple = await file.readObject('Data'),
+      selector = new TSelector();
+
+let nentries = 0;
+
+selector.addBranch('Bitset32');
+selector.addBranch('Bitset48');
+
+selector.Process = function(entry) {
+   nentries++;
+   const expected = {
+      Bitset32: 2 ** entry + 2 ** (31 - entry),
+      Bitset48: 2 ** entry + 2 ** (30 + entry) + 2 ** 47
+   };
+   for (const name in expected) {
+      const value = this.tgtobj[name];
+      if (value !== expected[name]) {
+         any_error = true;
+         console.error(`FAILURE: ${name} at entry ${entry} expected ${expected[name]} but got ${value}`);
+      } else
+         console.log(`OK: ${name} at entry ${entry} = ${value}`);
+   }
+};
+
+await rntupleProcess(rntuple, selector);
+
+if (nentries !== 10) {
+   any_error = true;
+   console.error(`FAILURE: expected 10 entries but got ${nentries}`);
+}
+
+if (any_error) {
+   console.error('\nFAILURE when reading std::bitset values');
+   process.exit(1);
+} else
+   console.log('\nTest OK');
diff --git a/demo/node/rntuple_bitset_test.root b/demo/node/rntuple_bitset_test.root
new file mode 100644
index 000000000..623cf19b2
Binary files /dev/null and b/demo/node/rntuple_bitset_test.root differ
diff --git a/modules/rntuple.mjs b/modules/rntuple.mjs
index dac1ded4b..6bdab8bc5 100644
--- a/modules/rntuple.mjs
+++ b/modules/rntuple.mjs
@@ -1210,7 +1210,7 @@ class BitsetReaderItem extends ReaderItem {
             if (this.bigint)
                res |= (1n << BigInt(len));
             else
-               res |= 1 << len;
+               res += 2 ** len;
          }
          len++;
       }