Venetoclax is a first-in-class orally available, B-cell lymphoma (BCL)-2 inhibitor indicated for the treatment of patients with relapsed/refractory chronic lymphocytic leukemia (CLL) harboring the 17p deletion. We used a novel approach for evaluating venetoclax pharmacokinetics using only sparse sampling in 155 patients enrolled in a phase 2, multicenter, open-label study in CLL patients with the 17p deletion. Patients received venetoclax doses within 30 min after the completion of breakfast or the first meal of the day, with no specific recommendations for the fat content in the meal. Blood samples for venetoclax assay were collected during the ramp-up period and on day 1 of weeks 8, 12, 16, 24, and every 12 weeks thereafter. The mean postdose (8 h) plasma venetoclax concentrations increased with increasing weekly venetoclax dose during the ramp-up period to reach 1.89 µg/ml on week 5 day 1 at the 400 mg dose. The mean predose concentration at the 400 mg dose ranged between 0.69 and 0.99 µg/ml across visits between weeks 8 and 120. Repeated-measures analysis detected no statistical significance (P≥0.05) for the mean predose concentrations at any of the times tested from weeks 8 to 24. The study shows that the pharmacokinetic profile of venetoclax in CLL patients with the 17p deletion is comparable to the overall CLL as well as non-Hodgkin’s lymphoma patient populations. Furthermore, no specific recommendation in terms of fat content in the meal is needed for the intake of venetoclax in patients with CLL.