To study the cardiohemodynamic changes following MAS, 39 newborn piglets(2.3-3.6kg 2-5 postn. day) were assigned to 4 grs; Gr. I: saline as control(6); Gr II: amniotic fluid (8) Gr III: Meconium with saline (8); GrIV:meconium with amniotic fluid (17). Intratracheal bolus of 3ml/kg of saline or aminiotic fluid or 3ml/ kg of 20% suspension of human meconium mixed with saline or with amniotic fluid were administered. Pulm. artery pressure (PAP), and cardiac output (CO) were measured by thermodilution technique. (mean±S.D.*p<.05 **p<.01 as compared c Gr I) Table GrIV also had sign. higher systemic BP at 2-8h, 9-24h, d-2, d-3 then Gr I. We concluded that MAS was associated with an increase in PAP and systemic BP; an increase in HR but unchanged CO, suggesting a decrease in stroke volume.