Clinical disease caused by weakly pathogenic mycobacterial species, Mycobacterium bovis Bacille Calmette-Guerin (BCG) and non-tuberculous environmental mycobacteria (EM), which is known as Mendelian susceptibility to mycobacterial disease (MSMD), is a rare entity defined recently. Infections with the more virulent Mycobacterium species, M. tuberculosis, may have largely gone unnoticed in these patients due to early death. Mutations in five proteins (IFN gamma R1, IFN gamma R2, IL-12/IL-23R beta 1, IL-12/IL-23p40 and STAT1) have been found in MSMD. These patients are prone to surprisingly few other infectious diseases mainly to salmonellosis. Here we present three IL-12/IL-23R beta 1 deficient patients from three different families and with different genetic mutations, who presented exclusively with Salmonella infections. Bacteremia and lymph node involvement were common clinical expressions. Leukocytoclastic vasculitis developed in one of these patients. Two patients were not inoculated with BCG, the third patient did not develop BCG infection although BCG vaccine had been given twice at ages of 1 and 7 years. All three patients responded well to antibiotic treatment. In conclusion, patients with chronic, recurrent or complicated Salmonella infections should be screened for MSMD, particularly for IL-12/IL-23p40/IL-12R/-23R beta 1 deficiency. Conversely, in patients with genetic IL-12/-23R beta 1 deficiency a full evaluation for Salmonella infection is required. IL-12/IL-23p40/IL-12R/IL-23R beta 1 deficiency seem to be underdiagnosed in patients with salmonellosis, and since such patients need prolonged therapy, diagnosis is important.