A telescopically extendable and collapsible ladder assembly having at least three ladder sections with two tubular stile members arranged parallel to each other and interconnected at one end by a ladder rung to form a U-shaped ladder section. The ladder assembly comprises latch mechanisms being associated with actuators for locking the telescopically inserted stile members relative to one another when the ladder sections are extended. Each ladder section includes a connector at each end of a rung, the connector having first and second collar segments with spaced apart opposed ends. A fastener bridges the opposed ends of the collar segments for securely coupling the collar segments around the stile member. The first collar segment extends over an angle of between 120 and 150 degrees with respect to the longitudinal axis of the rung, whereas the second collar segment extends over a complementary angle.