The effects of storage temperature on the composition of hop pellets of the varieties Brewers Gold, Efes Aroma, Galena, Northern Brewer and Saaz were studied. The hop pellets were stored at 3 degreesC and room temperature for 6 months in the dark. Chemical analyses showed that there were substantial losses of alpha- and beta-acids, soft resins and hop oil in all hop varieties stored at room temperature. These hop varieties showed a significant increase in hard resins at room temperature storage. Storing these varieties at 3 degreesC did not stop but slowed down these detrimental changes in hop composition. Changes in hop composition during storage were also dependent on the variety of hops used.