Abstract: Family planning utilization in Tanzania is low. This study was cross sectional. It examined family planning use and socio-demographic variables, social networks, knowledge and communication among the couples, whereby a stratified sample of 440 women of reproductive age (18-49), married or cohabiting was studied in Mwanza, Tanzania. A structured questionnaire with questions on knowledge, communication among the couples and practice of family planning was used. Descriptive statistics and Logistic regression were used to identify factors associated with family planning (FP) use at four levels. The findings showed that majority (73.2%) of respondents have not used family planning. Wealth was positive related to FP use (p=.000, OR = 3.696, and 95% C.I = 1.936 lower and upper 7.055). Religion was associated with FP use (p=.002, OR =2.802, 95% C.I = 1.476 lower and 5.321 upper), communication and FP use were significantly associated, (p=.000, OR = 0.323 and 95% C.I = 0.215) lower and upper = 0.483), social network and FP use (p=.000, OR = 2.162 and 95% C.I = 1.495 lower and upper =3.125) and knowledge and FP use(p=.000 , OR = 2.224 and 95% C.I = 1.509 lower and upper =3.278). Wealth showed a significant association with FP use (p=.001, OR = 1.897, 95% C.I = 0.817 lower and 4.404).Urban area was positively associated with FP use (p= .000, OR = 0.008 and 95% C.I = 0.001 lower and upper =0.09), semi urban was significant at (p= .004, OR = 3.733 and C.I = 1.513 lower and upper =9.211). Information, education and communication materials and to promote family planning in Tanzania should be designed and promoted.