A 76-year-old male diagnosed with interstitial pneumonia in December 2002 was treated with a steroid in a nearby hospital. Exacerbation of infectious pneumonitis and interstitial pneumonia required complementary inpatient treatment in August 2007. Although polymerase chain reaction examination of expectorated sputa revealed the absence of Mycobacterium tuberculosis, M. avium, and M. intracellulare on admission, nontuberculous M. abscessus was detected in the routine blood cultures. Taken together with clinical findings, M. abscessus was most likely the primary causative organism. Diagnosis of mycobaterium-induced septicemia generally involves the use of mycobacterium-designated bottles, MGIT method, and Ogawa medium; however, we used microbe cultures with routine blood-culture bottles in the present case. Of the 24 mycobacterium-induced septicemia cases reported in the past 10 years, only eight cases were detected from routine blood-culture bottles; they were all rapidly growing bacteria. Mycobacteria other than the rapidly growing mycobacteria display delayed culture proliferation, therefore it is possible that non-detected microbes were probably present in the patients despite the fact that they were suffering from septicemia. In cases suspected to have severe infections, particularly those with a depressed immunodefense system, blood-culture testing for mycobacteria would be highly helpful for diagnosis.