Abstract: A foldable baby stroller includes a main frame composed of a first section and a second section which is connected with each other by two retaining members. Two connection members are respectively pivotally connected to the first section by two position pins and are respectively secured to the second section. A U-shaped rear frame has two separating tubes and which are respectively connected to the two sections of the main frame. The retaining members are detachably connected to the second section so that when folding the stroller, the first section is pivoted to overlap onto the second section by disconnecting the retaining members from the second section, and the first section disconnecting from the separating tubes.