Background: United Nations International Children Emergency Fund (UNICEF) definesrnGrowth Monitoring and Promotion (GMP) is a prevention activity comprised of growthrnmonitoring linked with promotion (usually counseling) that increases awareness about childrngrowth; improves caring practices; increases demand for other services, as needed; and serves asrnthe core activity in an integrated child health and nutrition program, when appropriate. Thisrnwould help parents keep their young children healthy and well nourished. GMP has beenrnimplemented in Ethiopia since 2008 as nutrition specific intervention to prevent malnutrition.rnObjective: To assess knowledge and utilization of growth monitoring and promotion andrnidentify factor associated with knowledge and utilization of GMP for children under two years inrnButajira, SNNPR, Ethiopia.rnMethod: Community based cross sectional study was conducted from April-May 2017. A totalrnof 548 child mother pair less than 2 years old who resides in Butajira were selected by simplernrandom sampling method. Qualitative study (in depth interview and observation) were alsornconducted to supplement the quantitative study and to assess the skill and knowledge of healthrnextension workers working in selected heath post. The data was entered using Epidata versionrn3.1 and analyzed using STATA version 14 software. Multivariable logistic regression model wasrnfitted to predict the association between knowledge and utilization of GMP and theirrndeterminants. All statistical analysis was set at 5% level of significance (i.e. p < 0.05. The resultsrnwere reported as Odds Ratio and 95% CI). Appropriate tables and diagram were used to presentrnfindings.rnResult: Among 507 mother-child pair participates utilization of GMP was fifty five 11%rn[95%CI=8.4%-13.8%] while three hundred twenty five 64% [95%CI= 60%-68%] of the mothersrnhad adequate child feeding and growth chart knowledge. The result showed that mothers gavernbirth in the health facility were 1.60 times more likely to be knowledgeable about child feedingrnand growth chart than those mother gave birth at home [AOR=1.60; (95% CI=1.06, 2.44)].rnWhereas those child-mother pair traveled less than one hour to reach to the nearest health facilityrnfrom their house were 2.06 times more likely to be knowledgeable about child feeding andrngrowth chart than those mother travel more than an hour to reach to their nearest health facilityrn[AOR= 2.06; (95%CI=1.35, 3.13)]. Mothers with elementary educational level were 3.31 timernxiirnmore likely utilize GMP [AOR=3.31(95%CI=1.50, 6.02)] while mothers with secondary andrnabove education level were 3.33 times more likely utilize GMP than illiterate mothersrn[AOR=3.33(95%CI=1.30,8.50)]. Regarding occupation of the mother, framers were 4.03 timesrnmore likely utilize GMP than house wives [AOR=4.03(95%CI=1.32, 8.50)]. Mothers with childrnfeeding and growth monitoring adequate knowledge were about 5 times more likely utilize GMPrnthan those mother with inadequate knowledge [AOR=4.87(95%CI=1.80,13.16)]. Qualitatively,rnirregularity of GMP session due to health extension work load, not recording the age and weightrnof the child accurately, mother wrong belief and skill gap of heath extension workers werernchallenges of GMP utilization.rnConclusion: growth monitoring and promotion is not implemented as it was supposed to be.rnMore than half of the respondents had adequate child feeding and growth chart knowledge andrnutilization of GMP is very low in rural kebeles of Butajira. Monitoring implementation of growthrnmonitoring and promotion should be needed throughout different weredas and kebeles that arernexpected to implement growth monitoring and promotion program.