Within the discussion of voluntary proactive approaches to environmental protection, former microeconometric studies analyze the causal effect of the adoption of environmental management systems (EMS) on technological environmental innovations and find some positive impacts. Based on empirical studies which consider the effect of general innovativeness on the adoption of voluntary environmental programs (VEP) as well as based on insights from the resource-based view of the firm, we contrarily hypothesize in this paper that EMS could also reversely be affected by environmental product or process innovations. This hypothesis is empirically examined with a unique firm-level data set from the German manufacturing sector. Our econometric analyses with uni- and multivariate probit odels imply a significantly positive effect of environmental process innovations on certified EMS. According to this, the causal relationship between EMS and technological environmental innovations is obviously not clear.