Abstract: A tilt adjustment device includes tilt adjustment assemblies mounted on, and actuated by, a multi-sided bar, the entire device being mountable on a conventional venetian blind assembly for the purpose of providing separate adjustment of the venetian blind slats above the tilt adjustment device and those below the tilt adjustment device. The multi-sided bar passes through an aperture is a screw gear of the tilt adjustment assembly. The screw gear when rotated engages toothed gears in a slotted tilt adjuster, and the screw gear and the hexagonal bar are retained together by a housing. The tilt adjustment assembly and hexagonal bar can be easily attached to an existing venetian blind assembly, such as a mini-blind assembly. The device needs to be installed only once, and may be selectively raised and lowered on the ladder chords to suit the needs of the user. In use, the device can be vertically positioned and the slat pitch below the device can be adjusted in two easy motions.