A highly sensitive and selective voltammetric method was developed for the determination of curcumin using sodium dodecyl sulfate modified carbon nanocomposite paste electrode. The electrochemical performance for curcumin was characterized by the use of linear sweep voltammetry, cyclic voltammetry, and differential pulse voltammetry. These measurements showed that the sodium dodecyl sulfate modified carbon nanocomposite paste electrode provided excellent electrocatalytic enhancement for the oxidation of curcumin compared to an unmodified carbon nanocomposite paste electrode. Using the optimized conditions, the oxidation peak current showed a linear response from 2 × 10−7 to 1 × 10−6 M and 1.5 × 10−6 to 4.5 × 10−6 M with a detection limit equal to 2.7 × 10−8 M and limit of quantification equal to 9.2 × 10−8 M. The simultaneous determination of curcumin and vitamin B2 included a well resolved peaks, that provides rapid and selective analysis in the presence of vitamin B2. Moreover, the practical application of the developed electrode was performed for the analysis of a natural food supplement for curcumin.