Background: Exact determination between children's sleep habits and their growth could help us to prevent this risk factor of children's growth disorders. Thus this research was performed to investigate the correlation between sleep habits and growth of preschool children in Ahvaz-Iran. Materials and Methods: In this cross-sectional study, the data was obtained by using available sampling from 208 children of 3-6 years old that came to a private pediatric clinic in Ahvaz, South West of Iran in 2015 without regard to their gender. Measurement of height and weight of all patients with the meter and scale was performed. After measuring height and weight, stature-for-age and weight-for-age percentiles was calculated using child growth chart calculator of CDC for each child. Information on the onset time of night sleep, time to wake up in the morning and nap duration of children were gathered using researcher made questionnaire. Data analysis was performed with descriptive statistic and Kendall's tau-b statistical test using SPSS-19. Results: Results of this study showed of the 208 children that were evaluated, 32 of them (15.38%) was stunted, underweight, or both and 176 (84.6%) of them hadn't any growth disorder. Results of Kendall's tau test showed that there is no significant relationship between the onset time of night sleep, waking up time in the morning, nap duration and neither height-for-age percentile nor weight-for-age percentile of preschool children (P>0.05). Conclusion The results of this study showed that children sleep habits does not affect their stature and weight-percentile. But this isn't mean that going to sleep late has no effect on children's health, since the establishment of a normal sleep-wake rhythm is essential for both physical and mental development in children, so it is necessary to educate parents regarding the importance of children's sleep.