A description is given of cave diving accidents to British cave divers between 1946 and 1978. Eleven fatal accidents are described, of which the causes are generally multifactorial. Thirty-four non-fatal accidents are also mentioned and described under causal headings; it is shown that equipment failure or guide-line problems were present in 27 of these. During the 22 year period from 1957 to 1978 there were seven fatal accidents affecting cave divers in cave dives in the British Ilses. During the same period it is estimated that 4338 man-cave-dives were undertaken, giving a death rate per man-dive of 0.161%. During 1976 the British Sub-Aqua Club (B.S-A.C.) Recorded 5 deaths in a total of 437,863 man-open-water-dives, a death rate of 0.0011%. This difference is highly significant. Som eof the methods of preventing accidents, or of correcting them, are discussed.