The main body. The study involved students of the pharmaceutical faculty of the specialties of Pharmacy and Clinical Pharmacy of full-time education, during their training in III, IV and V courses. The study included two consecutive stages: I–survey of students on the questionnaire and analysis of their technological schemes for the manufacture of extemporal drugs in order to identify the technological operation, the implementation of which causes the greatest dif culty; ІІ stage–execution of the operation of the dosage with the subsequent determination of the error of weighing by the formula. As a result of the study, it was found that the operation, the execution of which causes the greatest dif culty, for most students (38.89%), is the dosage by weight, using both manual and tare scales. Conclusion. The examination of the dynamics of the learning of this skill by students in different periods of study has shown progress in mastering the ability to dosing by weight and improving the practical training of students, as facilitated by the integration of independent theoretical training with the development of the ability to weigh the substances under the direction of the teacher.