The incidence  of pericardial  effusion  in untreated   hypothyroidism  is

   reported to be 30%  to  80%.  The   study   of  pericardial effusion in primary

   hypothyroidism  was our objective.

         51patients with clinical or overt  hypothyroidism  and abnormal  thyroid

   function   test   was   admitted  to  internal  medicine   ward  in   Mobasher

   Kashani Hospital in Hamadan between1995-998.In all patients with clinical

   or overt hypothyroidism with raised TSH and lowT,  echocardiography  for

   persent pericardial effusion was done.

         In this study 51 patients with hypothyroidism  were studied(17 male and

   34 female) the  mean of age in this group was  47.41 years   with  minimum  

   16 years  and  maximum 75 years. Pericardial effusion was seen in different

   degree in 29 cases (56.9%).

         Pericardial effusion in primary hypothyroidism related with severity and

   duration    of   the   disease  .  Pericardial    effusion   may   be  a  frequent

   manifestation  in  advanced   severe  stage  and  myxedema  but  a  rare

   association of hypothyroidism in early mild stage.