Abstract: A pipette tip assembly is provided which includes one or more pipette tips, a tip support and a tip holder which is movable between a tip-holding and a tip-releasing position. The pipette tip assembly also includes a position-maintaining structure which is adapted to hold the tip holder in the tip-releasing position until the tip holder is selectively moved from that position. The position-maintaining structure thus eliminates or reduces the potential for inadvertent lifting of the tip holder relative to the assembly. The invention thus provides a pipette tip assembly that facilitates secure transport, minimal handling, and convenient and user-controlled operation.