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Grafham Water in Cambridgeshire is one of the most important wintering sites for waterfowl in Britain. Sailing there has relatively little impact on waterfowl because it occurs only intermittently and disturbance is more or less confined to deep water avoided by most waterfowl. However, bank and boat fishermen arrive in large numbers on every day during the fishing season, and often fish the shallow, sheltered bays and creeks favored by the birds. Detailed observations and results are presented for effects of fishing on numbers and distribution of waterfowl, grebes (Podiceps and Tachybaptus), and Eurasian coot (Fulica atra); an increase of waterfowl at the conclusion of the angling season; effects of the close of angling on distribution of wildfowl species; tolerance distance of mallards (Anas platyrhynchos) in specific areas in relation to disturbance and changes after angling closed; comparative approachability of water birds by area of the reservoir; and overall ranking orders for species based on bird counts and controlled approach studies. But ranking lists derived for Grafham might not be applicable elsewhere.