Context: Vitamins B1 (thiamine), B3 (niacin), B6 (pyridoxine), and C (ascorbic acid) are vital for energy, carbohydrate, lipid, and amino acid metabolism and in the regulation of the cellular redox state. Some studies have associated low levels of water-soluble vitamins with metabolic syndrome and its various components. Aims: This study aims to determine the plasma concentrations of vitamins B1, B3, B6, and C in Nigerians with metabolic syndrome and in healthy controls. Settings and Design: One-hundred subjects with metabolic syndrome were recruited into the study. One-hundred controls were age - and sex-matched. Materials and Methods: Blood pressure, body mass index, waist circumference, concentrations of plasma glucose, lipid profile, and vitamins B1, B3, B6, and C were estimated. Statistical analysis used: Statistical Package for Social Sciences (SPSS) version 11.0. Results: The mean plasma vitamins B1, B3, B6, and C concentrations of subjects were significantly lower than that of controls (P = 0.001, 0.05, 0.045, 0.001 respectively). Fourteen percent and 32% of subjects had inadequate vitamins B1 and C status, respectively. Vitamin B6 was lower (P = 0.001) and vitamin C was higher (P = 0.012) in female than in male subjects. Conclusions: Thiamine, niacin, pyridoxine, and ascorbic acid levels were lower in subjects than in controls. Pyridoxine was also lower and ascorbic acid was higher in female than in male subjects.