Method for designing a surgical guide for performing bone harvesting, including: • Providing a three-dimensional image of at least one portion of a bone of a patient (Pa) where said harvesting is to be performed, said bone defining an outer surface; • Identifying in said three-dimensional image one or more sensitive anatomic structures that must not be involved in said bone harvesting; • Identifying in said three-dimensional image a volume of bone suitable for being removed in said bone harvesting, said volume excluding said sensitive anatomic structures, and said volume being delimited by a portion of said outer surface of said bone defining a perimeter and by a mantle extending from said perimeter inside said bone, said mantle including, for each point of said perimeter, a segment forming a predetermined angle (a,b) with said portion of outer surface, said angle corresponding to a cutting direction (L1, L2, L3, L4) inside said bone identified in said three-dimensional image; • Establishing the parameters of said surgical guide, said step including: • defining a guide surface suitable for facing said outer surface of said bone, said guide surface comprising a work area delimited by guide walls (5a,5b,5c,5d); • Angling at least one of said walls with respect to said guide surface (5a,5b,5c,5d), so that said wall includes a face (7a,7b,7c,7d) that constitutes a geometrical extension of a portion of said mantle of said bone volume, when said guide faces said portion of outer surface of bone, so that said face includes, for each point of said perimeter of work area, a segment forming a predetermined angle with respect to said guide surface. • Providing a three-dimensional image of at least one portion of a bone of a patient (Pa) where said harvesting is to be performed, said bone defining an outer surface; • Identifying in said three-dimensional image one or more sensitive anatomic structures that must not be involved in said bone harvesting; • Identifying in said three-dimensional image a volume of bone suitable for being removed in said bone harvesting, said volume excluding said sensitive anatomic structures, and said volume being delimited by a portion of said outer surface of said bone defining a perimeter and by a mantle extending from said perimeter inside said bone, said mantle including, for each point of said perimeter, a segment forming a predetermined angle (a,b) with said portion of outer surface, said angle corresponding to a cutting direction (L1, L2, L3, L4) inside said bone identified in said three-dimensional image; • Establishing the parameters of said surgical guide, said step including: • defining a guide surface suitable for facing said outer surface of said bone, said guide surface comprising a work area delimited by guide walls (5a,5b,5c,5d); • Angling at least one of said walls with respect to said guide surface (5a,5b,5c,5d), so that said wall includes a face (7a,7b,7c,7d) that constitutes a geometrical extension of a portion of said mantle of said bone volume, when said guide faces said portion of outer surface of bone, so that said face includes, for each point of said perimeter of work area, a segment forming a predetermined angle with respect to said guide surface. • defining a guide surface suitable for facing said outer surface of said bone, said guide surface comprising a work area delimited by guide walls (5a,5b,5c,5d); • Angling at least one of said walls with respect to said guide surface (5a,5b,5c,5d), so that said wall includes a face (7a,7b,7c,7d) that constitutes a geometrical extension of a portion of said mantle of said bone volume, when said guide faces said portion of outer surface of bone, so that said face includes, for each point of said perimeter of work area, a segment forming a predetermined angle with respect to said guide surface.