Abstract: A polymer composition containing the following components in the hereinbelow-specified amounts, per cent by weight:______________________________________ poly-4-methylpenetene-1 or a copolymer of 4-methylpentene-1 with n-hexene 99.4 to 99.45 pentaerythritic ester of 4-hydroxy- 3,5-ditert . butylphenylpropionic acid 0.1 to 0.4 4,4'-dimethyl-6,6'-ditert . butyl-2,2'- methylenebisphenyl ester of .alpha.- naphthyl or phenylphosphorous acid 0.4 to 0.1 an anticorrosion additive 0.1 to 0.05. ______________________________________The polymer composition according to the present invention retains a high melt stability upon processing thereof to articles as well as possesses an increased resilience substantially unchanging during aging, and a high thermal stability. The polymer composition is useful in the medical and food industries, electrical and radio engineering.