Atomic force microscopy in its single-molecule force spectroscopy mode is a nanomanipulation technique that is extensively used for the study of the mechanical properties of proteins. It is particularly suited to examine their response to stretching (i.e., molecular elasticity and mechanical stability). Here, we describe protein engineering strategies and single-molecule AFM techniques for probing protein mechanics, with special emphasis on polycystic kidney disease (PKD) proteins. We also provide step-by-step protocols for preparing proteins and performing single-molecule force measurements.