diff --git a/plugins/libvirt/kvm_cpu b/plugins/libvirt/kvm_cpu
index 3196dc26..3f0faab7 100755
--- a/plugins/libvirt/kvm_cpu
+++ b/plugins/libvirt/kvm_cpu
@@ -83,7 +83,7 @@ def clean_vm_name(vm_name):
             return parts[parts.index('-name') + 1]
         except ValueError:
             pass
-    return re.sub(r"[^a-zA-Z0-9_]", "_", vm_name)
+    return re.sub(r"(^[^A-Za-z_]|[^A-Za-z0-9_])", "_", vm_name)
 
 
 def detect_kvm():
diff --git a/plugins/libvirt/kvm_io b/plugins/libvirt/kvm_io
index 1b84df15..62bc6a10 100755
--- a/plugins/libvirt/kvm_io
+++ b/plugins/libvirt/kvm_io
@@ -82,7 +82,7 @@ def clean_vm_name(vm_name):
             vm_name = parts[parts.index('-name') + 1]
         except ValueError:
             pass
-    return re.sub(r"[^a-zA-Z0-9_]", "_", vm_name)
+    return re.sub(r"(^[^A-Za-z_]|[^A-Za-z0-9_])", "_", vm_name)
 
 
 def fetch(vms):
diff --git a/plugins/libvirt/kvm_mem b/plugins/libvirt/kvm_mem
index 5cdeeac1..1d405fca 100755
--- a/plugins/libvirt/kvm_mem
+++ b/plugins/libvirt/kvm_mem
@@ -51,8 +51,8 @@ def clean_vm_name(vm_name):
             return parts[parts.index('-name')+1]
         except ValueError:
             pass
+    return re.sub(r"(^[^A-Za-z_]|[^A-Za-z0-9_])", "_", vm_name)
 
-    return re.sub(r"[^a-zA-Z0-9_]", "_", vm_name)
 
 def fetch(vms):
     ''' Fetch values for a list of pids
diff --git a/plugins/libvirt/kvm_net b/plugins/libvirt/kvm_net
index baea8449..8e9c5205 100755
--- a/plugins/libvirt/kvm_net
+++ b/plugins/libvirt/kvm_net
@@ -106,7 +106,7 @@ def clean_vm_name(vm_name):
             return parts[parts.index('-name')+1]
         except ValueError:
             pass
-    return re.sub(r"[^a-zA-Z0-9_]", "_", vm_name)
+    return re.sub(r"(^[^A-Za-z_]|[^A-Za-z0-9_])", "_", vm_name)
 
 
 def fetch(vms):