Off the top of my head I can think of two ways.Option 1: Cursorup_curs = arcpy.UpdateCursor(fc,"FIELD IS NULL")
for row in up_curs:
if not row.getValue(FIELD):
row.deleteRow(row)
Option 2: Select/Delete Features
arcpy.MakeFeatureLayer_management(fc,layer)
arcpy.SelectLayerByAttribute_management(layer,"FIELD IS NULL")
desc = arcpy.Describe(layer)
feat_count = int(arcpy.GetCount_management(parcel).getOutput(0))
feat_ids = desc.FIDSet
if feat_count > 0 and len(feat_ids) > 0:
arcpy.DeleteFeatures_management(layer)
Note: I haven't tested either of these so make sure you do some trials in a test environment.