Interpersonal relationships have been shown to be an important component of the psychosocial work environment that may affect health, job satisfaction, and productivity. The question whether interpersonal relationships at work are influenced by other psychosocial working conditions such as demands and control has not been studied. The aim of the present study is to investigate if high work demands and aspects of low work control could predict three indicators of detrimental interpersonal relationships at work. In a representative Swedish cohort study, data were obtained in two waves three years apart from 4049 participants, who did not change their jobs between the waves. These data were analysed by multiple logistic regression analyses. Odds ratios adjusted for possible confounders and negative interpersonal relationships at base-line showed that high demands predicted serious conflict and exclusion by co-workers. Low skill discretion predicted exclusion by co-workers. It is argued that these prospective findings are of relevance to interventions targeting troublesome and detrimental interpersonal relationships at work and that the findings can be important in understanding the development of work-related mental ill-health.