Abstract. A new short wavelength drift mode in tokamaks has been identified in stability analysis based on fully kinetic, electromagnetic integral equation code. The wavelength regime is in the electron skin depth and the instability is driven by toroidicity, electron temperature gradient, and magnetic shear. Ion temperature gradient has stabilizing influence. Both ions and electrons participate in the instability in nonadiabatic manner and the growth rate exhibits strong isotope effect being inversely proportional to the ion mass. The instability is stabilized in negative shear regime. It does not require trapped electrons and is resilient against finite beta stabilization.