This study was to determine the effect of picky eaters on the cognitive development of preschool children. The most highlighted child development is cognitive development. Cognitive is closely related to the ability to think. When children undergo activities, they will think. This development is also influenced by several factors, one of which is nutritional intake. This study used a qualitative research with a sample of 141 children. Institutions were chosen randomly, namely 4 preschool institutions in Karangploso sub-district. Picky eaters are measured by 5 subscales in the child eating behavior questionnaire (CEBQ), namely food avoidance satiety responsiveness (SR) avoiding food or getting full quickly; slowness in eating (SE) long chewing; fussiness (FF) fussy, food approach food responsiveness (FR) eating with coaxing; and enjoyment of food (EF). The results obtained are that 89.8% of children experience picky eaters and 9.2% of those who do not experience picky eaters. (SR) avoid food or get full quickly as much as 16.4%; slowness in eating (SE) 33.5% chewing time; fussiness (FF) fussiness as much as 50%. Based on the t-count value of -13.587 or smaller than the t-table of 1.977 and cognitive development of 0.00 or less than 0.05, then there is a correlation that children who are picky eaters will experience a decline in cognitive development.