Introduction: The first two years of life involve rapid physical, cognitive and social development that requires optimal nutrition. The transition from exclusive breastfeeding to family foods, referred to as complementary feeding, typically covers the period from 6 to 18-24 months of age, and is a very vulnerable period. Globally, 162 million under-five year olds were stunted in 2012. In 2012, 56% of all stunted children lived in Asia and 36% in Africa. Inappropriate feeding practices attribute to over two thirds of the annual under-five deaths globally, and occur during the period of infancy. Objective:To determine the prevalence of timely initiation of complementary feeding and its associated factors. Method: Institution based cross-sectional study was conducted in five health centers of kolfekeranyo sub-city from Feb.– March/2017.A total of 395 mothers or caregivers with 6- 23 months old child were interviewed using a structured questionnaire. The Collected data was checked every day by supervisors and principal investigator for its completeness and consistency. Binary logistic regression was used to see the association of each independent variable with dependent variable. Odds ratio and 95% CI was calculated and P-value < 0.05 considered as statistically significant. Ethical clearance was obtained from research ethics committee of Bahir Dar University. Result: prevalence of timely initiation of complementary feeding in the study area is 66.8%. After a multivariable analysis, knowledge about initiation time of complementary feeding [AOR=42.07, 95% CI: 5.352, 330.677, P-value=0.000], perception towards breast milk sufficiency for six months [AOR=8.05, 95% CI: 3.442, 18.827, P-value=0.000], unemployment [AOR=2.08, 95% CI: 1.276,3.393; P-value=0.003] and attending growth monitoring at health facility [AOR = 1.84,CI:1.104,3.053; P-value =0.019] remained significantly associated with timely starting complementary food for children. Conclusion and Recommendation: Around one third (33%) of the mothers/caregivers had not started complementary feeding at six months, despite what is recommended in national and global infant and young child feeding guidelines. Due attention should be given on practice of timely initiation of complementary feeding since numerous mothers/caregivers did not do so despite their knowledge about the time of initiation