Osteoclasts are notoriously hard to study because of the difficulty in obtaining pure populations of cells in large numbers for biochemical and molecular analyses. Unlike with other rodents (e.g., mice and rats), mature osteoclasts can be obtained from rabbits in relatively large numbers and can be purified easily. For some studies, such primary cultures of authentic osteoclasts may be preferable to osteoclast-like cells generated in vitro from bone marrow cultures. Isolated rabbit osteoclasts are capable of resorbing mineralized substrates in vitro and are therefore useful for assessing the effect of pharmacologic agents on osteoclast-mediated bone resorption (1,2). We and others have also extracted protein or RNA from purified rabbit osteoclasts for studies on metabolic processes in osteoclasts, or molecular studies on osteoclast biology using Western blotting, enzyme assays or reverse transcriptase-polymerase chain reaction (RT-PCR) (3–7).