A baby safety car seat having, at least when in use, a state in which it is convertible into a rollable baby seat, and comprising at least in said state: a lower, support portion including a seat lowermost area configured to contact an external surface to which the seat is to be mounted, and defining an imaginary horizontal base plane, an upper, seating portion having a front, head area and a rear, feet area, the head area being spaced from the base plane to a distance greater than the feet area; and a right and a left pair of front and rear legs (32, 34), the front and rear legs (32, 34) having distal ends associated with wheels (33, 35) and proximal ends, the legs being rotatable relative to the seat lower portion between a storage position to be taken in a safety car seat mode of the seat, in which the distal ends of the legs are disposed above said base plane, and an operational position to be taken in the rollable mode of the seat, in which the distal ends of the legs (32, 34) are disposed below said plane; characterised in that the front and rear legs of the right pair have a common right attachment area, at which the proximal ends of the front and rear legs (32, 34) of the right pair are articulated to the seat lower portion so as to enable their rotation with respect to each other,and the front and rear legs of the left pair have a common left attachment area, at which the proximal ends of the front and rear legs (32, 34) of the left pair are articulated to the seat lower portion so as to enable their rotation with respect to each other, the front and rear legs (32, 34) of each of the right and left pairs, when in the storage position, having their distal ends disposed under said head area of the upper seating portion. a lower, support portion including a seat lowermost area configured to contact an external surface to which the seat is to be mounted, and defining an imaginary horizontal base plane, an upper, seating portion having a front, head area and a rear, feet area, the head area being spaced from the base plane to a distance greater than the feet area; and a right and a left pair of front and rear legs (32, 34), the front and rear legs (32, 34) having distal ends associated with wheels (33, 35) and proximal ends, the legs being rotatable relative to the seat lower portion between a storage position to be taken in a safety car seat mode of the seat, in which the distal ends of the legs are disposed above said base plane, and an operational position to be taken in the rollable mode of the seat, in which the distal ends of the legs (32, 34) are disposed below said plane; characterised in that the front and rear legs of the right pair have a common right attachment area, at which the proximal ends of the front and rear legs (32, 34) of the right pair are articulated to the seat lower portion so as to enable their rotation with respect to each other,and the front and rear legs of the left pair have a common left attachment area, at which the proximal ends of the front and rear legs (32, 34) of the left pair are articulated to the seat lower portion so as to enable their rotation with respect to each other, the front and rear legs (32, 34) of each of the right and left pairs, when in the storage position, having their distal ends disposed under said head area of the upper seating portion.