Block mode of delivery, also known as intensive mode, has increasingly been adopted by courses in higher education institutions (HEIs) in recent years. This surge has been attributed to the efforts of HEIs to adapt to the changing student population, which involves a diverse student population, as well as the evolving education landscape, recently impacted by the COVID-19 pandemic. The distinctive nature of a block delivery model, and the impact of demographic, contextual and disciplinary factors on assessment performance makes an evaluation of student achievement in a block pedagogy a critical area of focus. The study presented here explores the impact of different types of summative assessment on student achievement in a block mode of delivery implemented across the different courses in a UKbased HEI. This is achieved using a quasi-experimental design, involving independent sample t-tests. The study firstly compared first and second year students’ grades in modules where summative assessment had been adapted for block, with students’ grades from the same modules that were traditionally taught in the previous year; and secondly examined the impact of different types of summative assessment in block delivery on students’ grades. Results indicate that adapting the type of assessment for block delivery had no statistically significant difference on students’ final grades. However, when comparing different types of summative assessments in block delivery, students achieved higher grades in time-constrained and multiple summative assessments, compared to single final essays (p<0.001 and Cohen’s d>0.5). The results from this study indicate that the type of summative assessment has an impact on students’ academic success and, therefore, this should be at the heart of staff training and curriculum design when adopting block delivery.