This chapter reviews the economics of criminal procedure, proceeding through four topics in the literature. First, it reviews the implications of substantive criminal law theories for criminal procedure. The second part discusses the error cost model of criminal procedure, which is the dominant framework and posits that criminal procedure rules are designed to minimize the sum of error and administrative costs. The third part reviews the public choice model of criminal procedure. Under this model, criminal procedure rules are designed largely to regulate rent-seeking activity. The last part of this chapter discusses some of the empirical work on procedure that bears directly on deterrence and welfare effects.