diff --git a/Doc/library/struct.rst b/Doc/library/struct.rst
--- a/Doc/library/struct.rst
+++ b/Doc/library/struct.rst
@@ -384,3 +384,7 @@
       The calculated size of the struct (and hence of the bytes object produced
       by the :meth:`pack` method) corresponding to :attr:`format`.
 
+   .. attribute:: nmemb
+
+      Number of members of the struct, corresponding to :attr:`format`.
+
diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py
--- a/Lib/test/test_struct.py
+++ b/Lib/test/test_struct.py
@@ -2,6 +2,7 @@
 import unittest
 import struct
 import sys
+import random
 
 from test.support import run_unittest
 
@@ -556,6 +557,45 @@
         s = struct.Struct('i')
         s.__init__('ii')
 
+    def test_Struct_nmemb(self):
+        fmtchars = "cbB?hHiIlLqQfdPsp"
+        nchars = len(fmtchars)
+        for _ in range(10):
+            n = random.randrange(1, nchars+1)
+            fmtlist = random.sample(fmtchars, n)
+            if 'P' in fmtlist:
+                # 'P' needs native mode, 'qQ' both need standard mode if 64-bit
+                # types are not available.
+                fmtlist[:] = [v for v in fmtlist if not v in 'qQ']
+                n = len(fmtlist)
+
+            for i, v in enumerate(fmtlist[:]):
+                if random.randrange(2):
+                    # Insert repeat count.
+                    x = random.randrange(1000000)
+                    fmtlist[i] = str(x) + v
+                    if v != 's' and v != 'p':
+                        n += (x - 1)
+
+            if random.randrange(2):
+                # Insert padding character.
+                i = random.randrange(len(fmtlist))
+                fmtlist.insert(i, 'x')
+
+            # Insert mode character.
+            if any('q' in v.lower() for v in fmtlist):
+                fmtlist.insert(0, random.choice("=<>!"))
+            elif random.randrange(2):
+                order = "@"
+                if not any('P' in v for v in fmtlist):
+                    order += "=<>!"
+                fmtlist.insert(0, random.choice(order))
+
+            fmt = ''.join(fmtlist)
+            s = struct.Struct(fmt)
+            self.assertEqual(s.nmemb, n)
+
+
 def test_main():
     run_unittest(StructTest)
 
diff --git a/Modules/_struct.c b/Modules/_struct.c
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -1665,6 +1665,12 @@
     return PyLong_FromSsize_t(self->s_size);
 }
 
+static PyObject *
+s_get_nmemb(PyStructObject *self, void *unused)
+{
+    return PyLong_FromSsize_t(self->s_len);
+}
+
 /* List of functions */
 
 static struct PyMethodDef s_methods[] = {
@@ -1687,6 +1693,7 @@
 static PyGetSetDef s_getsetlist[] = {
     {"format", (getter)s_get_format, (setter)NULL, "struct format string", NULL},
     {"size", (getter)s_get_size, (setter)NULL, "struct size in bytes", NULL},
+    {"nmemb", (getter)s_get_nmemb, (setter)NULL, "number of struct members", NULL},
     {NULL} /* sentinel */
 };