The mean of weight increment at moult for 11 females (41-71 mm CL) and 12 males (35-76 mm CL) of Palinurus elephas (Fabr., 1787) held in tanks was calculated by weekly weight data. The higher percentage of weight increment ( 82% and 73% respectively in females and males) occurs in a week before the exuviation when the spiny lobsters cease feeding (K fase). 7-10 days after exuviation they resume eating; their shells are completely hardened in one month (T fase). Then the weight remains constant during the following S fase until the next K fase