Introduction There is very limited published experience with intravenous (IV) antituberculosis (anti-TB) and antiretroviral therapy (ART) especially in children. We have described a human immunodeficiency virus (HIV)-infected child with complicated abdominal tuberculosis who was initially treated with IV anti-TB and a partially IV ART regimen before transitioning to oral therapy. Patient presentation A 3-year-old boy presented with hypovolaemic shock with a 3-day history of inability to pass stools, abdominal distension and bile-stained vomiting. Abdominal ultrasound and X-ray showed small-bowel obstruction. Human immunodeficiency virus antibody testing was positive, and Cluster of Differentiation (CD)4+ lymphocyte count was 56 cells/mL (15%). Xpert Mycobacterium tuberculosis (MTB)/Rifampicin (RIF) Ultra and TB culture on induced sputum detected MTB complex sensitive to rifampicin and isoniazid. Management and outcome Following laparotomy and closure of bowel perforations, the child was commenced on IV rifampicin, moxifloxacin and amikacin. Amikacin was stopped after 3 days because of nephrotoxicity, and meropenem and IV linezolid were added. After 20 days, ART comprising IV zidovudine, oral lamivudine solution, oral lopinavir/ritonavir solution and additional oral ritonavir solution for super boosting was commenced. By day 40, the patient was well established on oral feeds and was switched to standard oral anti-TB medications. Sputum examined 1 month after starting the treatment was found culture-negative for MTB. After 4 months of treatment, the HIV viral load was < 100 copies/mL. He completed a total of 12 months of anti-TB treatment. Conclusion Despite limited experience and few available IV formulations of standard anti-TB and ARV medications, initial IV therapy may be beneficial for patients in whom oral medication is not an option.