Proportions of classical (CD14++CD16−), intermediary (CD14+CD16+) and non-classical (CD14lowCD16+) peripheral blood monocytes were measured before and one week, one month and one year after kidney allograft transplantation. Results from patients with uncomplicated outcomes (n=94) were compared with those with acute rejection (n=44). The number of CD14+CD16-monocytes increased immediately after transplantation, declined at one month and further upregulated one year post-transplant in both groups. The number of CD14+CD16+ monocytes decreased after transplantation, increased at one month and declined at one year. CD14lowCD16+ monocytes decreased dramatically after transplantation and remained lower than pre-transplant values, with a further decline at one year. In blood samples taken on the day of diagnostic biopsy confirming positive for acute rejection, no changes were observed compared to other post-transplant samples. Data are expressed as mean ± SEM; * p<0.05.