In a multi-piece solid golf ball which includes a core of at least one layer, a cover of at least one layer, and at least one intermediate layer interposed between the core and the cover, the cover is composed primarily of polyurethane and the following parameters are controlled within specific ranges: core deflection, melt flow rate of intermediate layer material, thickness of intermediate layer, thickness and Shore D hardness of cover, combined thickness of intermediate layer and cover, and the value of (Shore D hardness of cover material)(Shore D hardness of intermediate layer material). This golf ball has a good, soft feel at impact and lowers the rate of spin on full shots, achieving a good distance.

In a golf ball having, in order, a core, an envelope layer, an intermediate layer and a cover, the following conditions are satisfied: (I) ball surface hardness>intermediate layer surface hardness>envelope layer surface hardness<core surface hardness, (II) (Shore D hardness at core surfaceShore D hardness at envelope layer surface)10, (III) (cover thicknessintermediate layer thickness)>0.05 mm, (IV) (intermediate layer thicknessenvelope layer thickness)>0.05 mm, and (V) (CsC.sub.10)/(C.sub.10Cc)>1.0 (where Cs denotes the JIS-C hardness at the core surface, C.sub.10 the JIS-C hardness at a position 10 mm from a center of the core, and Cc the JIS-C hardness at the core center). The ball provides an excellent flight performance when struck by the average golfer, a feel that is both soft and solid, and an excellent durability to repeated impact.

A golf ball including a core; an inner cover layer formed from a thermoplastic composition and having a thickness of about 0.005 inches to 0.40 inches and a surface hardness of about 60 Shore D or greater; and an outer cover layer formed from a thermoset material and having a thickness of about 0.01 inches to 0.05 inches and a surface hardness of about 60 Shore D or less. The thermoplastic composition has a first melt flow index at 280 C. under a 10-kg load of less than about 35 g/10 min and a second melt flow index at 265 C. under a 5-kg load of less than about 10 g/10 min.

A golf ball includes a core, a mid layer, and a cover. A slope A1 of a straight line connecting a central point of the core and a point at 2.5 mm from the central point and a slope A2 of a straight line connecting the point at 2.5 mm and a point at 5.0 mm from the central point are each 1.00 or more. A slope A5 of a straight line connecting a point at 10.0 mm from the central point and a point at 12.5 mm from the central point and a slope A6 of a straight line connecting the point at 12.5 mm and a point at 15.0 mm from the central point are each 1.50 or more. The cover is formed of a resin composition containing an ionomer resin, with the ionomer resin present in an amount of 60% by mass or more.