This was a cross sectional study which was conducted to estimate the family size and to identify the factors influencing family size in rural areas of Bangladesh. Respondents of 150 households were interviewed through interview schedule and in-depth questionnaires. The size of the family was observed as 4.59 persons’ where nearly half of the respondents (48%) having less than five members. A~e of the respondent, number of children, age of the first and last child, average monthly income, number of rooms in the house, persons living in the main dwelling houses, number of earning persons having audio-visual assets had statistically significant association with the size of the family and all were with higher percentage in big family. Middle-income group was more in the small and big family category (75% and 65.40% respectively).