Bacteriological examination was carried out on twenty faecal samples of dogs, 10 from apparently healthy dogs and 10 from dogs showing diarrhoea. The results of anaerobic culture examination of faecal samples of the dogs suffered from diarrhoea revealed the isolation of Cl. perfringens type A (80%), Cl. perfringens type B (50%), Cl. difficile (60%) as well as Cl. fallex and Cl. sporogens (30 and 10%, respectively). Anaerobic culture examination of faecal samples of five children suffering from diarrhoea revealed the presence of Cl. perfringens type A and B and Cl. fallex (60, 20 and 40%, respectively). Cl. difficile was isolated from diseased children for the first time in Egypt in a percentage of 40%. Moreover, Cl. perfringens type A, Cl. fallex and Cl. sporoqens were isolated from five apparently healthy children at the same percentage of 20%. Experimental infection of puppies with Cl. perfringens type A per Os showed several clinical symptoms and post mortem lesions characteristic to this type of infection. The inoculated strain was re-isolated from the intestinal contents. The suggested role of dogs in transmitting infection to human beings was discussed.