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Weathering pits (gnammas, Opferkessel, pias) are described from two granite outcrops developed on pediment surfaces in the Spitzkoppe area of the Namib Desert, central Namibia. The paper provides morphometric data and a discussion of the sediments on the pit floors. A classification of pits, based on their pathways of development is presented, and some hypotheses of origin are discussed. The pits are a significant component of the outcrops, occupying 25 to 33 per cent of their surface areas. They are also significantly larger than those reported in previous studies from other granite areas, though the reasons for this are not clear. Weathering pit formation appears to be an important process in causing pediment development and in reducing surface relief.