The present invention relates to a liquid pharmaceutical composition comprising a granulocyte colony stimulating factor polypeptide conjugated with a polymer. In various embodiments, the composition has a pH value in the range of 4.5 to 5.5. Exemplary compositions further comprise a surfactant and optionally one or more other pharmaceutically acceptable excipients. The invention provides, inter alia, formulations free from tartaric acid or salts thereof and/or from succinic acid and salts thereof as buffering agents. Exemplary formulations are essentially devoid of not amino acids as stabilizers. The composition has good storage stability and is especially useful for the prophylaxis and treatment of disorders and medical indications where granulocyte colony stimulating factor preparations are considered as useful remedies.