A viscoelastic polyurethane foam formed from a polyisocyanate and a polyol composition comprising palm olein-based polyol in an amount of 10% to 35% by weight of the total polyol composition and petroleum-based polyol in an amount of 65% to 90% by weight of the total polyol composition. The dissipation energy of the viscoelastic polyurethane foam is between 0.01 J to 0.30 J as calculated based on a hysteresis loop normalized a density of 40.80 kg/m3. This shows that the viscoelastic foam produced has an improved dampening property. The introduction of palm olein-based polyol into the production of viscoelastic foam does not affect the support factors and mechanical properties of the foam produced. The viscoelastic foams can be produced using an amount of up to 35% of palm olein-based polyol derived from palm olein or up to 25% of palm olein-based polyol derived from a mixture of palm olein and soybean oil by weight of total composition without any adjustment in the catalyst package.