Creatinine, calcium (Ca), p hosp hate, immunoreactive p arathyroid hormone (i PTH) and calcitonin (i CT) blood levels were measured before and after haemodialysis (HD) in 24 p atients submitted to regular dialysis treatment, and in the days following successfui rén a l tr a nspl a nt a tion (RT) in other p a tients i PTH a nd i CT levels were elev a ted before HD; the rise of pl a sm a C a following HD w a s a ccomp a nied by a decrea se in i PTH (P < 0.001), where a s i CT wa s incre a sed, though not signi fic a ntly. The levels of i PTH a nd i CT, eleva ted before RT, returned to norma l a fter RT, together with cre a tinine a nd P levels ; a rejection a fter some d a ys in 2 p a tients w a s followed by a r a pid incre a se in i PTH a nd i CT levels. One p a tient who underwent subtot a l p a r a thyroidectomy 281 d a ys a fter RT bec a use of persistent hyperc a l c a emi a a nd high i FTH levels is a lso presented.