diff --git a/avocado/utils/cpu.py b/avocado/utils/cpu.py
index 45457366bbe2ae4f64600411c8f267ac07f63649..41653d514b5c6f1e14ae939d0f914aeca58d0dbd 100644
--- a/avocado/utils/cpu.py
+++ b/avocado/utils/cpu.py
@@ -22,6 +22,7 @@ Get information from the current's machine CPU.
 
 import re
 import os
+import platform
 
 
 def _list_matches(lst, pattern):
@@ -136,10 +137,15 @@ def cpu_online_list():
     Reports a list of indexes of the online cpus
     """
     cpus = []
+    search_str = 'processor'
+    index = 2
+    if platform.machine() == 's390x':
+        search_str = 'cpu number'
+        index = 3
     with open('/proc/cpuinfo', 'r') as proc_cpuinfo:
         for line in proc_cpuinfo:
-            if line.startswith('processor'):
-                cpus.append(int(line.split()[2]))  # grab cpu number
+            if line.startswith(search_str):
+                cpus.append(int(line.split()[index]))  # grab cpu number
     return cpus
 
 
diff --git a/selftests/unit/test_utils_cpu.py b/selftests/unit/test_utils_cpu.py
new file mode 100644
index 0000000000000000000000000000000000000000..b9f877e61c1cb503e4b20233830a5e2356cabd5e
--- /dev/null
+++ b/selftests/unit/test_utils_cpu.py
@@ -0,0 +1,92 @@
+import io
+import unittest
+
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
+
+from avocado.utils import cpu
+
+
+class Cpu(unittest.TestCase):
+
+    @staticmethod
+    def _get_file_mock(content):
+        file_mock = mock.Mock()
+        file_mock.__enter__ = mock.Mock(return_value=io.StringIO(content))
+        file_mock.__exit__ = mock.Mock()
+        return file_mock
+
+    def test_s390x(self):
+        s390x = u"""vendor_id       : IBM/S390
+# processors    : 2
+bogomips per cpu: 2913.00
+max thread id   : 0
+features        : esan3 zarch stfle msa ldisp eimm dfp edat etf3eh highgprs te sie
+facilities      : 0 1 2 3 4 6 7 8 9 10 12 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 30 31 32 33 34 35 36 37 40 41 42 43 44 45 46 47 48 49 50 51 52 57 73 74 75 76 77
+cache0          : level=1 type=Data scope=Private size=96K line_size=256 associativity=6
+cache1          : level=1 type=Instruction scope=Private size=64K line_size=256 associativity=4
+cache2          : level=2 type=Data scope=Private size=1024K line_size=256 associativity=8
+cache3          : level=2 type=Instruction scope=Private size=1024K line_size=256 associativity=8
+cache4          : level=3 type=Unified scope=Shared size=49152K line_size=256 associativity=12
+cache5          : level=4 type=Unified scope=Shared size=393216K line_size=256 associativity=24
+processor 0: version = FF,  identification = 32C047,  machine = 2827
+processor 1: version = FF,  identification = 32C047,  machine = 2827
+
+cpu number      : 0
+cpu MHz dynamic : 5504
+cpu MHz static  : 5504
+
+cpu number      : 1
+cpu MHz dynamic : 5504
+cpu MHz static  : 5504
+
+"""
+
+        s390x_2 = u"""vendor_id       : IBM/S390
+# processors    : 4
+bogomips per cpu: 2913.00
+max thread id   : 0
+features        : esan3 zarch stfle msa ldisp eimm dfp edat etf3eh highgprs te sie
+facilities      : 0 1 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 30 31 32 33 34 35 36 37 40 41 42 43 44 45 46 47 48 49 50 51 52 57 64 65 66 67 68 69 70 71 72 73 75 76 77 78 131 132
+cache0          : level=1 type=Data scope=Private size=96K line_size=256 associativity=6
+cache1          : level=1 type=Instruction scope=Private size=64K line_size=256 associativity=4
+cache2          : level=2 type=Data scope=Private size=1024K line_size=256 associativity=8
+cache3          : level=2 type=Instruction scope=Private size=1024K line_size=256 associativity=8
+cache4          : level=3 type=Unified scope=Shared size=49152K line_size=256 associativity=12
+cache5          : level=4 type=Unified scope=Shared size=393216K line_size=256 associativity=24
+processor 0: version = 00,  identification = 3FC047,  machine = 2827
+processor 1: version = 00,  identification = 3FC047,  machine = 2827
+processor 2: version = 00,  identification = 3FC047,  machine = 2827
+processor 3: version = 00,  identification = 3FC047,  machine = 2827
+
+cpu number      : 0
+cpu MHz dynamic : 5504
+cpu MHz static  : 5504
+
+cpu number      : 1
+cpu MHz dynamic : 5504
+cpu MHz static  : 5504
+
+cpu number      : 2
+cpu MHz dynamic : 5504
+cpu MHz static  : 5504
+
+cpu number      : 3
+cpu MHz dynamic : 5504
+cpu MHz static  : 5504
+"""
+
+        with mock.patch('avocado.utils.cpu.platform.machine', return_value='s390x'):
+            with mock.patch('avocado.utils.cpu.open',
+                            return_value=self._get_file_mock(s390x)):
+                self.assertEqual(len(cpu.cpu_online_list()), 2)
+            with mock.patch('avocado.utils.cpu.open',
+                            return_value=self._get_file_mock(s390x_2)):
+                self.assertEqual(len(cpu.cpu_online_list()), 4)
+
+
+if __name__ == "__main__":
+    unittest.main()