We study numerically existence of invariant and ergodic measures in the model of dynamics of blood-forming system.Existence of such measures is connected with irregular (chaotic) behaviour of a system.We consider the first order delay differential equation in the form proposed by A.Lasota:dN(t)/dt =-N(t)+(N(t-h))n e ()()()()where N(t) is the amount of erythrocytes in the blood circulation, h is a delay and , , are the parameters which have biological interpretation.