The present invention relates to a heat-sealable film which consists essentially of a cycloolefin copolymer (COC), the glass transition temperature (Tg) of the COC being within the range from 30 to 55.degree. C. The film or sheet has excellent low temperature heat-sealing properties and processing characteristics. The film may be free standing or laminated to other thermoplastic polymer film or films at low temperatures. Alternatively, a COC polymer with Tg in the range 30 to 55.degree. C. may be coextruded with other thermoplastic polymer or polymer films in a coextrusion process to form a heat sealable film. The film of the invention is suitable for packing foods or other consumable items.