The effect of N-2 pressure and laser fluence on the chemical composition and growth rate of CNx (0.07 < x < 0.45) films deposited by ArF excimer laser ablation of a graphite target in nitrogen environment is reported, Between 1 and 50 Pa the nitrogen content of the films monotonously increases with increasing pressure, Films deposited at various N-2 pressures differ not only in their (average) nitrogen but also in their oxygen content. The chemical composition of the films deposited using pulses of influences between 0.7 and 2 J cm(-2) remains the same within experimental error, while in the 2-10 J cm(-2) domain the nitrogen incorporation steeply increases, The growth rates vary from 0.003 to 0.56 Angstrom /pulse, increasing linearly with fluence and decreasing with increasing pressure in the 0.7-2 J cm(-2) fluence domain, while followed by a supralinear dependence on fluence and less sensitivity to N-2 pressure at higher fluences. Changes in film porosity account for the striking features reported.