The intensity fluctuations of the radiation of an optical parametric oscillator have been calculated by taking into account the corresponding fluctuations of the pump light. The latter are shown to have a strong influence on the fluctuations of signal and idler waves. In contrary to the laser case, they are essentially reproduced in the signal and idler radiation; more quantitatively, the correlation function 〈ϱ(t1) ϱ(t2)〉 where ϱ denotes the deviation of the amplitude of the signal (or idler) wave from its mean value is, for t1 = t2, equal to the corresponding quantity for the pump wave apart from a reduction factor, whose value depends on the resonator losses and the relative excitation of both the pumping laser and the optical parametric oscillator and is found to be of the order of one for the normal case. It is interesting to note that for sufficiently strong pumping, the correlation function 〈ϱ(t1) ϱ(t2)〉 approaches the value zero for |t1t2| [RIGHTWARDS ARROW] ∞ not monotonically but in form of damped oscillations.