Alternative, antibody-free techniques to western analysis of protein blots can offer reduced assay times for routine analysis of expression of recombinant proteins. We have adapted the commercially available enzyme fragment complementation technology to provide a rapid protein detection method for protein blots based on significantly reducing the number of incubation and washing steps used in traditional approaches, and eliminating the requirement for antibodies. In this chapter, we highlight the use of this assay for measuring recombinant protein expressed in mammalian cells for a range of applications, including dot blot screening of large numbers of different cell samples, assessment of protein integrity through detection of degradation bands, and characterization of posttranslational protein modifications such as glycosylation.