The standard methods of pH titration of ion exchangers, the direct titration and the batch method, are usually applied to macroscale amounts of resin (about 5-20 g). Attempts to adjust these methods to the microscale are described. Titrations were carried out with suspended 100 mg portions of different types of ion exchangers. The capacity values Q(0) determined, expressed as mequiv/g of dry resin, correspond satisfactorily with those obtained by macrodeterminations (e.g., Kunin’s method). The validity of the Q(0) data obtained strongly depends on the precision and accuracy of the determination of moisture contents. Due to results of gravimetric and thermoanalytical measurements, it seems to be impossible to determine a definite "true", "accurate" value of the water content by means of a heating procedure. However, microdeterminations of capacity values based on the combined methods of pH titration and a drying procedure reveal a marked ruggedness, so that a sufficient reliability can be obtained.