This chapter describes the use of 3D printing techniques in biochemistry, including cell biology, molecular biology, and in vitro drug screening. The toxicity of different 3D print resins and polymers, and the measures to improve their biocompatibility using post-UV treatment, heat treatment, and surface modification are also discussed. A wide range of cell culture devices have been 3D-printed to generate single cells (1D), cell clusters (2D), and cell spheroids (3D) for cellular assays, and 3D-printed ‘organs-on-a-chip’ have been developed to assist drug discovery. 3D-printed microfluidic platforms have been developed to perform rapid disease diagnosis and to study cell and molecular biology. 3D printed devices enabling polymerase chain reactions have facilitated this vital diagnostic procedure in resource-limited locations. New cell sorting and electroporation systems have been developed to provide high performance at low-cost. Bespoke biosensors have been 3D-printed with encapsulated enzymes and antibodies for bio-recognition.