Giant liposomes composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol are imparted with cationic or anionic charge by incorporation of 2-20% cationic or anionic lipids. Although two giant liposomes of like charge do not adhere, two giant liposomes of opposite charge will (depending upon the % of ionic lipid) either adhere slowly on contact, "snap together" instantly, or adhere with severe membrane distortions and even membrane layering. It was also observed that the bursting of a cationic liposome attached to an anionic liposome can be stimulated by adhesion of a second cationic liposome to the anionic liposome at a site distant from the first adhesion site. Addition of a cationic or anionic surfactant to two adhered liposomes of opposite charge causes the two liposomes to drift apart. The effect, however, is only transitory because the surfactant can redistribute itself into the interior of the liposome, thereby diminishing the surfactant’s contribution to the surface charge. Ca2+ induces adhesion between two noncharged liposomes, but here too the effect is only temporary since the Ca2+ can diffuse into the interliposomal liquid.