A solventless silicone release composition comprising the following components,,, and: alkenyl-containing organopolysiloxane containing at least two alkenyl groups per molecule and having a vinyl value of 0.016 mol/100 g to 0.7 mol/100 g and a kinematic viscosity at 25°C of 80 mm 2 /s to 500 mm 2 /s, when measured by an Ostwald viscometer, represented by the general formula M α M vi β D γ D vi δ T ε T vi ζ Q η wherein M is R 3 SiO 1/2, M vi is R 2 PSiO 1/2, D is R 2 SiO 2/2, D vi is RPSiO 2/2, T is RSiO 3/2, T vi is PSiO 3/2, Q is SiO 4/2, each R independently is a C 1 -C 12 substituted or unsubstituted monovalent hydrocarbon group free of aliphatic unsaturation, P is an alkenyl group of the formula -(CH 2) a -CH=CH 2 wherein a is an integer of 0 to 6, α, β, δ and ζ are each independently an integer of at least 0, not all of β, δ and ζ being 0 at the same time, 2 ≤ β+δ+ζ ≤ 50, γ is an integer of 10 to 300, ε is an integer of 0 to 20, and η is an integer of 0 to 10, organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule and having a kinematic viscosity at 25°C of 2 mm 2 /s to 500 mm 2 /s, when measured by an Ostwald viscometer, in an amount to give 1 to 5 moles of silicon-bonded hydrogen atoms per mole of alkenyl groups in component, an effective amount of platinum group metal base catalyst, 0.1 to 10 parts by weight, per 100 parts by weight of component, of organopolysiloxane containing a crosslinked structure and having fluidity, and 0.1 to 10 parts by weight per 100 parts by weight of component of a high-molecular-weight linear organopolysiloxane having the general formula: M 1 2 D Ψ wherein M 1 is R 1 3 SiO 1/2, D is as defined above, R 1 is a C 1 -C 12 substituted or unsubstituted monovalent hydrocarbon group free of aliphatic unsaturation or a hydroxyl group, and Ψ is a positive number of 300 to 3,000. alkenyl-containing organopolysiloxane containing at least two alkenyl groups per molecule and having a vinyl value of 0.016 mol/100 g to 0.7 mol/100 g and a kinematic viscosity at 25°C of 80 mm 2 /s to 500 mm 2 /s, when measured by an Ostwald viscometer, represented by the general formula M α M vi β D γ D vi δ T ε T vi ζ Q η wherein M is R 3 SiO 1/2, M vi is R 2 PSiO 1/2, D is R 2 SiO 2/2, D vi is RPSiO 2/2, T is RSiO 3/2, T vi is PSiO 3/2, Q is SiO 4/2, each R independently is a C 1 -C 12 substituted or unsubstituted monovalent hydrocarbon group free of aliphatic unsaturation, P is an alkenyl group of the formula -(CH 2) a -CH=CH 2 wherein a is an integer of 0 to 6, α, β, δ and ζ are each independently an integer of at least 0, not all of β, δ and ζ being 0 at the same time, 2 ≤ β+δ+ζ ≤ 50, γ is an integer of 10 to 300, ε is an integer of 0 to 20, and η is an integer of 0 to 10, organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule and having a kinematic viscosity at 25°C of 2 mm 2 /s to 500 mm 2 /s, when measured by an Ostwald viscometer, in an amount to give 1 to 5 moles of silicon-bonded hydrogen atoms per mole of alkenyl groups in component, an effective amount of platinum group metal base catalyst, 0.1 to 10 parts by weight, per 100 parts by weight of component, of organopolysiloxane containing a crosslinked structure and having fluidity, and 0.1 to 10 parts by weight per 100 parts by weight of component of a high-molecular-weight linear organopolysiloxane having the general formula: M 1 2 D Ψ wherein M 1 is R 1 3 SiO 1/2, D is as defined above, R 1 is a C 1 -C 12 substituted or unsubstituted monovalent hydrocarbon group free of aliphatic unsaturation or a hydroxyl group, and Ψ is a positive number of 300 to 3,000.