Introduction: Patients on hemodialysis (HD) or peritoneal dialysis (PD) were consistently reported to have a high prevalence of vitamin D deficiency. However, there are limited data among Asian population. Objective: To assess the prevalence of Serum 25(OH)-vitamin D deficiency in patients on maintenance HD and PD in Sarawak General Hospital. Methods: This cross sectional study was conducted from November 2015 to September 2016. Patients were classified as vitamin D deficient (<20 ng/ml), insufficient (21 and 29 ng/ml) or sufficient (>30 ng/ml). Results: Of the 170 patients, 101 were on HD and 69 were on CAPD. In HD patients, vitamin D deficiency was found in 7.9% of the patients (n ¼ 8), and insufficiency in 22.8% (n ¼ 23). In CAPD patients, vitamin D deficiency was found in 49.3% of the patients (n ¼ 34), and insufficiency in 30.4% (n ¼ 21).Among HD patients, those with serum 25(OH)D concentrations of <30 ng/ml were predominantly female (p¼ 0.000) and diabetic (p¼0.003). There were significant correlation between serum 25(OH)D and body mass index (p ¼ 0.026), waist circumference (p ¼ 0.031), dialysis vintage (p ¼ 0.005), and magnesium (p ¼ 0.001). There was no correlation with age, corrected calcium, albumin, phosphate, alkaline phosphatase, or intact parathyroid hormone level.Among PD patients, those with serum 25(OH)D concentrations of <30 ng/ml were predominantly female (p¼ 0.004), Malay race (p ¼0.000), urban locality (P ¼0.013) and diabetic (p¼0.000). There was no significant correlation with all the other demographic or laboratory parameters. Conclusions: Our study showed that vitamin D deficiency/insufficiency is highly prevalent among PD patients. However, the majority of our HD patients are not vitamin D deficient. Other risk factors identified include diabetes, female gender, and urban locality. Interestingly, the prevalence of vitamin D deficiency is very low among the Bidayuh patients. Further studies are needed to explore the reason for this and also the consequences of vitamin D deficiency and possible therapeutic interventions.