This is a five year study from 1981 to 1986 which attempts to consolidate and analyze the collection of income taxes levied on professionals in private practice in the Philippines particularly those affecting professionals residing within Quezon City. It will also discuss its implications to Nigeria's tax system. More specifically, the following questions will be answered: (1) What are the bases for taxing professionals? (2) How large is the group of professionals, and how much has the government collected from them? (3) What problems have surfaced from the professionals in private practice with regard to filling their income taxation? (4) What measures may be adopted to improve collections from professionals in private practice? and (5) What are some implications for Nigeria's tax system? The subject of taxation is as old as any form of government, for no governmental function can be carried out without funds raised through some forms of exaction from its inhabitants. However, an overview of the subject matter as presented in this study would widen the perspective for all - Bureau of Internal Revenue, students/teachers, professionals in private practice, legislative and the general public.