A method and apparatus (10) for custom blending spray paints. A customer provides a sample (S) of a color to be matched. The sample is tested on a spectrophotometer to determine the colors needed to match the sample; or if the paint formula is known, it is entered into the apparatus. A computer control (16) causes metered quantities of each colorant to be pumped from a reservoir (50) to a manifold (68). From the manifold, paint is injected through a filling head (46) into a discharge valve (V) and dip tube (P) of a precharged aerosol container (C) to be filled. Solvent from a tank (74) is used between a final injection of colorant to flush out the manifold and a dip tube (P) of the container. After the colors have been injected into the container, the container is shaken so that the colors intermix with each other to produce a paint of the desired custom color which is readily sprayed from the container.