HAEMOLYTIC streptococci were first subdivided into groups by precipitation of specific carbohydrate (Lancefield, 1933, 1934). It soon became apparent that most serious streptococcal infections were caused by organisms of Group A. Although organisms of Group B were known to cause mastitis in cattle there was little evidence of pathogenic activity in man. Then in 1937 Colebrook & Purdie included two examples in a description of 106 cases of puerperal fever. In the next year Fry (1938) recorded three fatal Group B infections in the puerperium and Brown (1939) published an account of four such infections, two of them puerperal. He stated that, of all strains of streptococci with ,8-haemolysis isolated by him, 1-6 % belonged to Group B. Rantz & Kirby (1942) described four more such infections and again drew attention to its occurrence in puerperal states. Wheeler & Foley (1943) mentioned six patients, four of whom died, from whom this organism was isolated, but gave no clinical details. In 1947, the Commission on Acute Respiratory Disease, dealing with American recruits, reported that only 6% of hospital admissions were caused by streptococcal infection, of whom 90% were attributable to Lancefield Group A and 'a few' to Group B. Thereafter, little was written on the subject until, in 1961, Hood, Janney & Dameron suggested that the incidence of Group B streptococcal infection in the newborn at least was higher than had been thought. They cultured the brains of 113 non-viable foetuses and stillborn infants. Streptococcus agalactiae was recovered from nearly 10%. Keitel et al. (1962) reported two newborn infants from whom the organism was isolated in the cerebro-spinal fluid. In both cases the same organism was cultured from the mothers' cervices and both babies died. Mannik et al. (1962) described a 29-day-old infant, in whom meningitis due to Group B streptococci was successfully treated. This is one of the three cases of recovery from the disease in the newborn recorded. Eickoff (Eickoff et al., 1964) recorded seven infants from whom /3-haemolytic streptococci Group B were cultured from the blood, four of whom died. In three others positive blood cultures were considered unrelated to their illnesses. In none of these babies was meningitis present. Sicherman (1965) described two siblings, aged 2 and 3 years with septicaemia, but no meningitis, from both of whom Group B streptococci were isolated from the blood. During this latter period seven examples of Group B meningitis have been published in the continental literature (de Moor, 1960; Seeleman, 1941; Obiger, 1964; Kexel & Khonhohn, 1965. De Moor's infant was the second to recover. Finally in 1966 Winterbauer, Fortune and Eickhoff described two newborn infants with meningitis caused by this organism. These occurred within a few days of each other in a small hospital and one of them survived after treatment with penicillin and kanamycin. No instances of Group B meningitis in the newborn have been described to date in the British Isles. We therefore report two such cases occurring in the same hospital.