Curcumin, a natural yellow pigment with a wide spectrum of bioactivities, was incorporated in nanocomposite films of cassava starch with poly(vinyl alcohol) (PVA) for achieving sustained release properties which improves its potential for use in cancer treatment. The ultra structure of the films was studied by scanning electron microscopy (SEM) and the formation of nanoparticles was confirmed by transmission electron microscopic (TEM) analysis. The curcumin incorporation in the films was confirmed by Fourier transform infra red spectroscopy (FTIR). The swelling capacity and erosion of the films were also recorded. It was observed that pH of the medium and storage conditions greatly affected the release of curcumin from the polymer matrices. The release behaviour of curcumin from starch‐PVA matrices was studied and the kinetics behind the curcumin release was fitted to Higuchi model. The mechanism obtained from Korsemeyer‐Peppas equation was a combination of diffusion and erosion controlled. Cytotoxicity study of the incorporated curcumin was carried out with normal as well as cancer cells and the results showed that it was non‐toxic to normal cells and it also showed anticancer potential. The cell viability (%) in the case of cancer cells was lower for nanocomposite incorporated curcumin than pure curcumin which indicates higher anti cancer potential of the former. The size of curcumin was reduced in the nanocomposites as evidenced from TEM and SEM analysis results, which might have resulted in its greater cell availability and resultant higher anticancer activity.