Pakistan is at middle stage of demographic transition with high population growth rate compared with many other developing societies. This high growth rate primarily is due to the large family size, which is defined within the socio-cultural dimensions of the society. The enormous population growth hinders the socio-economic development of society. This study will particularly explore the socio-economic and cultural aspects of family size and son preference. The present study was an attempt to investigate the various factors faced by urban people in the social, economic and cultural fields. The major objective of the study was to determine the family size under the influence of desire family and son preference in urban areas of district Faisalabad. Through random sample method, Faisalabad city was selected. In Faisalabad city, three areas i.e. Tariq Abad, Raza Abad and Peoples Colony No. 1, were selected by using simple random method from the list of areas in Faisalabad city. A sample of 150 married females of age 15 - 45 (reproductive behavior) having at-least one children were selected. 50 respondents were selected by using snow ball sampling techniques were applied for the selection of sample in the selected area. It is concluded those socio-economic characteristics in term of women education, family income and demographic factors: age at marriage has being upon the family size.