The study of marketing-manufacturing integration (MMI) in new product development (NPD) projects is rather limited, and has not clearly indicated how levels of MMI should differ across various stages of development for high and low levels of product innovativeness. Our study builds upon prior research that has applied resource dependency theory to product development projects. We examine the influences of MMI in each of four stages of the NPD process. A path analysis of data drawn from 467 completed NPD projects indicates that stronger MMI accomplished early in NPD is associated with stronger MMI in later stages of NPD. For highly innovative projects, increased MMI in each stage of product development is respectively associated with greater product market success, but MMI in the earliest stages is especially salient. For incremental NPD projects, the strongest positive associations of MMI with product market success are indicated in product commercialization. We compare our findings with prior research, and we identify benefits, detriments, and costs of MMI that should be more deeply explored in future research with the objective of a more complete theory of cross-functional integration in NPD.