A current-mode chaotic oscillator based only on current mirrors is studied. The oscillator is suitable for synchronization and application in secure communications. It operates on high frequencies and is suitable for on chip implementation. Its chaotic behavior is controlled by means of a bias voltage. Various methods for detecting chaos, such as the Lyapunov exponents, the Lyapunov dimension, the spectrum and the phase portraits are used, in order to confirm the chaotic behavior of the circuit. Simulation results fully coincide with theoretical results.