Curriculum development is a dynamic and continuous process, it is subject to change in view of the changing socio-economic and political scenario. It is changed when it is not consistent with the national aspirations and goals of education. It is changed when it loses balance, integration and relationship within and among various disciplines. Biology as an important scientific discipline, has been gaining currency doing the last three decades, and plays significant role in the field of science. It helps in understanding ourselves, our environment and the world around us. Such were the guiding spirit that inspired the researcher to study in depth the nature and process of changes and developments of biology curriculum offered at secondary level in Pakistan Since 1 960. The main objectives governing the study are to study the nature of changes brought about in biology curriculum, to identify factors and forces warranting such changes, to identify the problems and issues inhibiting proper implementation of die curriculum in the class room and also to formulate guide-lines for not only correcdng the situation but to make it more responsive to the challenges of the 21stcentury. The study is hoped to in faience the policy of the government and will provide feed back on the operational status of the curriculum. The study is descriptive in nature and is based on documentary analysis and field assessment of the execution of the subject in the class room. Documentary analysis is based on critical review of all related documents formulated from time to time by the government on biology. The field analysis is based on comments observations of the heads of institutions teachers, biologists and educationists on the nature, scope and relevance of biology curriculum, the infra-structure and the instructional facilities provided for effective teaching of the subject. On the basis of analysis and other situational factors, it is concluded that biology curriculum has been widely diversified in nature and scope and has been sufficiently expanded vertically and horizontally. But wide margins have been left for changing its descriptive nature, ensuing its integration within itself and among other scientific disciplines and projecting more its social aspect and practical approach to the solution of social problems, besetting the society. The subject further needs to be future oriented not only perceiving the future problems of the society but incorporating the explosive nature of knowledge and information, shifting its classical and traditional mode of instruction to the emerging innovative use of sophisticated instructional technology in teaching of biology curriculum in future.