Microcapsules, a process for preparing the same, and a pressure-sensitive recording paper containing the same are disclosed. The microcapsules are prepared by a process which comprises polymerizing melamine and formaldehyde, or polymerizing initial condensates of melamine and formaldehyde, around hydrophobic oil droplets containing a polyisocyanate or a prepolymer of polyisocyanate, wherein a polyhydroxy compound is incorporated into said hydrophobic oil droplets prior to microencapsulation, thereby producing a sturdy double wall made of of polyurethaneurea film (inner wall) and melamine/formaldehyde resin film (outer wall).