Changes in hepatopancreas mass in nymphs, male and female Scorpio maurus fuscus (Scorpiones, Scorpionidae) from northern Israel, were followed through the year, and its percentage water content calculated. The hepatopancreas mass was positively correlated with body mass in males, females and nymphs, and changed significantly with season. In nymphs it ranged between 0.1549 g and 0.5351 g, in males between 0.1631 g and 0.3431 g, and in females between 0.2240 g and 0.6669 g. The hepatopancreas mass of males differed significantly from that of females during summer and autumn, and from nymphs during summer and winter. The hepatopancreas mass of nymphs differed significantly from that of females during autumn, winter and spring. In females, the hepatopancreas mass increased from autumn to spring. During that time, the embryonic diverticula (Ed) containing the embryos increase in number and size during embryogenesis. The depletion of the hepatopancreas mass is positively correlated with the Ed during the latter part of the gestation period before parturition. The percentage water content of the hepatopancreas ranged between 47.8% and 68.4%, and varied seasonally as well as between the genders. It is suggested that these changes in both hepatopancreas mass and water content are related to physiological events such as growing and moulting in nymphs, feeding and mating activities in males and the oogenetic cycle in females.