Aim: The aim of this study was to determine the frequency of varicella zoster virus (VZV) infection in patients undergoing allogeneic haematopoietic stem cell transplant (allo-HSCT) in a single hospital. Method: This retrospective study included all patients who underwent allo-HSCT during the period of April 2004–December 2014 in The Aga Khan University Hospital in Pakistan. Medical records were reviewed to determine the proportion of allo-HSCT patients who developed VZV infection. Results: The study included 133 patients, of whom 93 (70 %) were male and 40 (30 %) were female. The median patient age was 20 years, and all patients received prophylactic antiviral therapy. After transplant, ten patients developed VZV infection, with a median patient age of 16.5 years, and a median time to VZV infection of 302 days (range 102–805 days). The most common underlying diagnosis was aplastic anaemia. Of the ten affected patients, nine responded to therapeutic doses of aciclovir or valaciclovir, and one was lost to follow up. Conclusion: In our study, the frequency of VZV infection following allo-HSCT was lower than that commonly reported in the international literature.