diff --git a/quantities/unitquantity.py b/quantities/unitquantity.py
index 9ecc0eb..fc4d3e8 100644
--- a/quantities/unitquantity.py
+++ b/quantities/unitquantity.py
@@ -382,6 +382,14 @@ class UnitInformation(IrreducibleUnit):
 class UnitCurrency(IrreducibleUnit):
 
     _primary_order = 9
+    
+class UnitLogIntensity(IrreducibleUnit):
+
+    _primary_order = 10
+    
+class UnitLogPower(IrreducibleUnit):
+
+    _primary_order = 11
 
 
 class CompoundUnit(UnitQuantity):
diff --git a/quantities/units/__init__.py b/quantities/units/__init__.py
index 48a34fe..ed74fae 100644
--- a/quantities/units/__init__.py
+++ b/quantities/units/__init__.py
@@ -42,6 +42,9 @@
 from . import length
 from .length import *
 
+from . import logunits
+from .logunits import *
+
 from . import mass
 from .mass import *
 
diff --git a/quantities/units/logunits.py b/quantities/units/logunits.py
new file mode 100644
index 0000000..4594515
--- /dev/null
+++ b/quantities/units/logunits.py
@@ -0,0 +1,27 @@
+"""
+"""
+from __future__ import absolute_import
+
+from ..unitquantity import UnitLogIntensity, UnitLogPower, UnitQuantity
+
+bel = UnitLogIntensity(
+    'bel',
+    symbol='bel'
+)
+decibel = dB = UnitQuantity(
+    'decibel',
+    bel / 10,
+    'dB'
+)
+
+bel_milliwatt = UnitLogPower(
+    'bel_milliwatt',
+    symbol='Bm'
+)
+decibel_milliwatt = dBm = UnitQuantity(
+    'decibel_milliwatt',
+    bel_milliwatt / 10,
+    symbol='dBm'
+)
+
+del UnitLogIntensity, UnitLogPower, UnitQuantity