This book is prepared solely for the student preparing for the examination of accountancy body in Sri Lanka and to provide guidance to income tax payer how to compute an individual income tax and their business tax. I hope that, it includes all the business related taxes. Especially University students, Higher National Diploma in Accountancy (HNDA) students, Chartered Accountancy Examination(ICASL) students, Association of Accounting Technicians students AAT (SL), External B.com, other management related students and Diploma in Banking and Finance (DBF) students can refer this book for the preparation of their examination and helps to succeed in the subject. The basic structure of tax doesn’t change regularly on the other hand some amendments or changes may be done by the government in every budget.