The measurement of skeletal maturity is important for the analysis of growth and growth disorders. Several methods are available for the assessment of skeletal age. They are all based on the recognition of maturity indicators, that is, of changes in the radiographic appearance of hand-wrist bones. The most commonly used methods are the Greulich and Pyle Atlas and the Tanner-Whitehouse (TW2) method. More recently, the FELS method has been described by Roche and coworkers. The assessments made using the Greulich and Pyle Atlas are often very inaccurate, whereas experience with the FELS method is still very limited. At the present time, the TW2 is still the method of choice. It is hoped that the development of a computerized method of assessment will lead to greater accuracy in the determination of skeletal maturity.