Lameness can be defined as a variance from the normal gait or stance of an animal. Lameness is not itself a disease but can be a sign of a disease process, pain, impediment, deformity or weakness. There are usually multiple tissues or joints involved. This is especially true with chronic ongoing lameness. In these cases there is a primary problem with associated secondary, tertiary or quaternary problems. These can be very complex cases and may involve multiple visits to the Veterinarian before a true diagnoses is determined. A diagnostic plan can help to simplify the work-up. Two cases involving a rear-leg lameness are described to help demonstrate the process.