The influence of photodegradation on the optical limiting process of chloroform solutions of chlorophyll A is investigated. Optical limitation experiments were carried out with a frequency-doubled, 10 ns Nd:YAG laser at a 5 Hz repetition rate, as a function of sample degradation. Optical limitation becomes less effective in photodegraded samples, which may be explained by the decrease in the concentration of chlorophyll A molecules. It is concluded that the optical limiting process is mainly related to the reverse saturated absorption mechanism, and contributions from light scattering due to photodegradation and the cavity bubbles appear irrelevant.