Optical remote sensing can highlight recurring and anomalous algal blooms in marginal and enclosed seas. The SeaWiFS-derived (1998-2003) database of chlorophyll-like pigment concentration (chl) was used to monitor algal growth in the Mediterranean basin. Yearly and monthly chl means were computed for the 6 years available, and climatological mean images derived. Then, interannual and seasonal variability was assessed computing yearly and monthly chl anomalies, as the difference between each individual year/month and the corresponding climatological year/month. The analysis of these anomalies provides a novel insight into the Mediterranean biological cycles, demonstrating algal blooms dynamics and related environmental boundary conditions.