A method of making bottom-gusseted packages, comprising the steps of: providing a flexible web of material having a longitudinal axis, providing a plurality of folded, individual sleeves; joining said individual sleeves to said flexible web in spaced apart relationship longitudinally of said flexible web, with the spacing between said individual sleeves corresponding to the length of each of said bottom-gusseted packages being formed, with laterally-extending portions of each individual sleeve oriented toward a bottom of the respective package; folding said flexible web of material and joining the lateral margins thereof to form a folded flexible web, and to thereby form a package body for each of said bottom-gusseted packages, each package body including a front package panel and a rear package panel joined at opposite side margins thereof, said individual sleeves being positioned generally within said folded flexible web to form a bottom gusset in the respective one of said packages, providing a pair of cooperating sealing jaws for heat-sealing each of said individual sleeves to form the bottom gusset in each one of said packages, and cutting said folded flexible web at intervals each corresponding in length to said length of each of said bottom-gusseted packages, to form said bottom-gusseted packages, the method being characterized in that: said sealing jaws includes respective, cooperating, U-shaped sealing surfaces each including: a pair of side sealing surfaces to heat-seal opposite lateral margins of each individual sleeve to the respective front and rear package panels (14, 16) at lateral margins thereof, and a transverse sealing surface extending between said side sealing surfaces to respectively heat-seal said laterally-extending portions of each sleeve to the front and rear package panels (14, 16) at the bottom of each one of said packages, and said pair of side sealing surfaces of each one of said sealing jaws includes sealing surfaces for heat-sealing said front and rear package panels (14, 16) to each other above the respective one of said individual sleeves forming said bottom gusset. providing a flexible web of material having a longitudinal axis, providing a plurality of folded, individual sleeves; joining said individual sleeves to said flexible web in spaced apart relationship longitudinally of said flexible web, with the spacing between said individual sleeves corresponding to the length of each of said bottom-gusseted packages being formed, with laterally-extending portions of each individual sleeve oriented toward a bottom of the respective package; folding said flexible web of material and joining the lateral margins thereof to form a folded flexible web, and to thereby form a package body for each of said bottom-gusseted packages, each package body including a front package panel and a rear package panel joined at opposite side margins thereof, said individual sleeves being positioned generally within said folded flexible web to form a bottom gusset in the respective one of said packages, providing a pair of cooperating sealing jaws for heat-sealing each of said individual sleeves to form the bottom gusset in each one of said packages, and cutting said folded flexible web at intervals each corresponding in length to said length of each of said bottom-gusseted packages, to form said bottom-gusseted packages, the method being characterized in that: said sealing jaws includes respective, cooperating, U-shaped sealing surfaces each including: a pair of side sealing surfaces to heat-seal opposite lateral margins of each individual sleeve to the respective front and rear package panels (14, 16) at lateral margins thereof, and a transverse sealing surface extending between said side sealing surfaces to respectively heat-seal said laterally-extending portions of each sleeve to the front and rear package panels (14, 16) at the bottom of each one of said packages, and said pair of side sealing surfaces of each one of said sealing jaws includes sealing surfaces for heat-sealing said front and rear package panels (14, 16) to each other above the respective one of said individual sleeves forming said bottom gusset. said sealing jaws includes respective, cooperating, U-shaped sealing surfaces each including: a pair of side sealing surfaces to heat-seal opposite lateral margins of each individual sleeve to the respective front and rear package panels (14, 16) at lateral margins thereof, and a transverse sealing surface extending between said side sealing surfaces to respectively heat-seal said laterally-extending portions of each sleeve to the front and rear package panels (14, 16) at the bottom of each one of said packages, and said pair of side sealing surfaces of each one of said sealing jaws includes sealing surfaces for heat-sealing said front and rear package panels (14, 16) to each other above the respective one of said individual sleeves forming said bottom gusset.