Non-exclusive breastfeeding is defined as the provision of food or fluids in addition to drugs, vitamins, and minerals to infants before the age of 6 months. Exclusive breastfeeding for infants is seen to prevent and cure stunting and other forms of malnutrition. Primary Health Care (PHC) Margorejo is the health center with the lowest exclusive breastfeeding coverage in Pati Regency in 2017 and 2018. The purpose of this study was to analyze the factors related to the behavior of non-exclusive breastfeeding in the working area of the PHC Margorejo in Pati Regency. This study uses a case control method. The research sample consisted of 70 consisting of 35 cases and 35 controls. The research targets were mothers who have 6-11 months old infants in the working area of the PHC Margorejo. Bivariate analysis showed a low level of maternal knowledge (p = 0.008), negative maternal attitudes (p = 0.022), and the absence of support from health workers (p = 0.002) related to non-exclusive breastfeeding behavior. Low level knowledge of mothers, negative attitude of mothers, and the absence of support from health workers are all factors related to the behavior of non-exclusive breastfeeding in the working area of PHC Margorejo in Pati Regency.