Abstract Aim Diabetic nephropathy (DN) is a devastating complication of diabetes mellitus (DM). Therefore, screening strategies in order to prevent its development and/or retard its progression are of paramount importance. We investigated if monocyte chemoattractant protein‐1 (MCP‐1) was associated with new onset microalbuminuria‐the earliest sign of the albuminuric phenotype of DN‐ in patients with type 2 DM and normoalbuminuria. Methods We measured MCP‐1 in serum and urine samples from patients of the Randomized Olmesartan And Diabetes Microalbuminuria Prevention (ROADMAP) study and its Observational Follow‐up (OFU) cohort. A case control design was used with inclusion of 172 patients who developed microalbuminuria (MA) and of 188 well matched controls who remained normoalbuminuric. Results The median duration of follow‐up for the ROADMAP cohorts was 6.5 years, whereas the mean time until occurrence of MA was 53.2 months. In the multivariate analysis, serum and urine MCP‐1 remained significant predictors of new onset MA. The risk for MA increased continuously with increasing serum and urine MCP‐1 levels but reached statistical significance only in the highest quartiles. The risk associations were stronger with serum MCP‐1. Conclusions MCP‐1 is a marker and possibly a mediator of early diabetic nephropathy. Further prospective studies are necessary to test whether diabetic patients with elevated MCP‐1 levels would benefit from specific therapeutic interventions.