In this study, we measured the serum-urine total carnitine levels and PTH levels before and after treatment in 18 patients with nutritional rickets. The urine and blood samples were taken on the first (pretreatment) and the 15th day of the study (post-treatment). The total carnitine levels of serum and urine samples, serum PTH and serum-urine creatinine concentrations were determined. We found that the levels of carnitine excreted in the urine on the first (pre-treatment) and on the 15th day (post-treatment) were higher than the reference levels. Decrease in carnitine excretion on the 15th day seemed to be correlated with decrease in aminoaciduria at that time. The study showed a significant correlation between urinary carnitine excretion and serum PTH levels. In our study we did not find any significant difference between the serum total carnitine levels on the first (pre-treatment) and the 15th day (post-treatment), and both values were lower than the reference values for the same age group. We observed that the total serum carnitine levels did not change on the 15th day of the post-treatment period in spite of a decrease in urinary carnitine excretion. The results of the present study indicated that carnitine metabolism is disturbed in nutritional rickets. Further evaluation of rickets cases and new studies will probably lead to a better understanding of carnitine metabolism in nutritional rickets.