Myopathies are a heterogeneous group of disorders that can be challenging to diagnose. This review provides a diagnostic approach based predominantly on the clinical history and neurologic examination. Laboratory testing that can be used to confirm the suspected diagnosis based on this pattern recognition approach is also discussed. Careful consideration of the distribution of muscle weakness and attention to common patterns of involvement in the context of other aspects of the neurologic examination and laboratory evaluation should assist the clinician in making a timely and accurate diagnosis and can sometimes minimize the expense of further testing.