The occurrence and treatment of palatal fistulae have been studied in 1108 CLP patients who had their primary operations performed during the years 1954–69. No fistulae were recorded in 263 patients with incomplete cleft of the primary palate only. These patients were excluded, leaving 845 patients for analysis. The Le Mesurier or Millard technique had been used for the primary lip operation, and the von Langenbeck procedure for closure of the palate; in complete clefts, the anterior part of the palate had been closed using Veau's vomer flap operation simultaneously with lip closure. The observation period ranged from 7 to 22 years, during which time each patient was examined at least once and the majority on several occasions by members of the cleft palate team. The overall incidence of fistulae was 18%. Fistulae were recorded in 11.3% of all complete clefts of the primary palate, and in 36.1% of all complete total clefts. In cases of cleft palate only, fistulae were found in 3.5% of the incomplete clefts, and in 20% of the complete clefts. In patients with bilateral complete clefts, closure of both sides of the lip and anterior palate in one operation seemed to have greatly increased the risk of fistula formation. There was a much higher incidence of fistulae in patients operated on during the years 1954–61 than in those treated in the period 1962–69. Fistula symptoms requiring surgical intervention were recorded in 113 patients. Closure of the fistula was achieved in 84.1%. Of 18 patients with a residual fistula. 17 were asymptomatic or had symptoms so slight that they were considered insignificant and not justifying operation.