Xeroderma pigmentosum (XP) is an autosomal recessive disorder caused by defect in nucleotide excision repair and is associated with increased incidence of skin cancer. Lymphoblastic leukemia in XP is rare. We report a case of a 11-year-old boy with XP, who developed B – Acute lymphoblastic leukaemia (ALL). He was started on Modified BFM (Berlin-Frankfurt-Münster) ALL Protocol. Tolerance to ALL chemotherapy was good in our XP patient except for the transient derangement of liver function tests during induction, Pseudomonas sepsis and oral mucositis during protocol M and hyperbilirubinemia during maintenance chemotherapy. Though rare, children with XP requires to be investigated for acute leukaemia on development of bicytopenia.