Objective: To identify factors associated with the delaying of language development in 18 months to 3-years-old children in Naresuan University Hospital.

Materials and Methods: The case-control study included 30 delayed language development and 30 normal development children at 18 months to three years of age. Characteristics of children, mother, father, and caregiver were interviewed. Daily activities of children were reviewed. The data were analyzed by Chi-squere test.

Results: Twenty-three boys and seven girls were included in both study case and control groups. Mean age (±SD) were 2.0±0.5, 2.0±0.4 years in case group and control group, respectively. Mothers of children who had delayed language usually had a bachelor’s degree or higher. These children spent time to play alone more than one hour per day and spent time to watch TV or other media for more than two hours per day.

Conclusion: Factors association for delayed language development in 18 months to 3-years-old children in Naresuan University Hospital were high education mother, children that spend time to play alone for more than one hour per day, and children that watched TV or other media for more than two hours per day.

Keywords: Delayed language development, Risk factors, Children