The aim of the study was to investigate the effects of hypovitaminosis D on pain, quality of life (QoL) and nerve conduction studies (NCSs) in patients with chronic widespread pain (CWP). We randomly selected 83 female patients with CWP according to their vitamin D levels in this cross-sectional study. Patients were divided into two groups as sufficient vitamin D level (above 20 ng/ml) and deficient vitamin D level (below 20 ng/ml, hypovitaminosis D). Various pain scales and Nottingham Health Profile (NHP) were used. NCSs were also done. In patients with hypovitaminosis D, there were significantly higher pain scores for all scales (p value range 0.002-0.027). The subscale and total NHP scores were significantly higher in hypovitaminosis D group (p = 0.048-0.001) except social isolation subscale (p = 0.553). Vitamin D levels were in negative correlation with right and left median and/or ulnar motor nerve amplitudes, left tibial motor amplitude. This study confirm that hypovitaminosis D is related with higher pain intensity and lower QoL scores in patients with CWP when compared with control group. Additionally, we identified for the first time that there were negative correlations between vitamin D levels and some findings of NCSs.