Problem-based learning (PBL) is an instructional approach that challenges students to think critically and work cooperatively in groups to seek solutions to real-world problems. These problems serve as cognitive stimulus to arouse students' curiosity and initiate learning of disciplinary subject content matter. Authentic assessment modes play a key role in the efficacious implementation of a PBL curriculum. This paper discusses student learning experiences in a tertiary institution that follows a PBL-based curriculum, involving 25 first year students ranging in age from 17 to 19 and evenly balanced in terms of gender. Qualitative data was collected from students' postings in their reflection journals, and key themes were analyzed and identified. Students found the assessment system to be robust, and the different modalities improved their higher-order thinking skills, communications, and collaboration abilities. Some key issues focusing on the drawbacks of authentic assessment modalities in the PBL environment were raised as including lack of consistent and objective grading, etc.