I introduce a minimum innovation size required for patents into a Schumpeterian growth model. We show that to satisfy the patentability requirement for minimum innovation size, each research and development (R&D) firm targets only industries in which the incumbent's technology is of sufficient obsolescence. This is because the technological gap between innovator and incumbent is greater in industries using older technologies. Although the increase in minimum innovation size reduces the number of industries targeted for R&D, it also increases the amount of R&D investment directed at those targeted industries. Consequently, introducing a minimum innovation size has a nonmonotonic (or negative) effect on the aggregate flow of innovations. Further, by deriving the endogenous long-run distribution of innovation size, we show that an increase in minimum innovation size reduces the mean innovation size. This implies that even if the patent office only grants patents for superior innovations, it causes innovators to produce generally inferior-quality innovations.