Abstract: Seed priming have been used successfully in an attempt to improve germination and seedling establishment of many vegetables and field crops. The objective of this research was to study the effect of polyethylene glycol (PEG) 8000 concentrations and seed treatment durations on soybean seed germination. Three experiments were conducted: In experiment 1, the seeds were treated for 1, 2, or 7 days. The osmotic potentials of the PEG solutions were 0, -0.1, -0.2, -0.4, -0.5, -0.7, and -1.1 MPa including control. In control the seeds were treated with water for the above duration. In experiment 2, the seeds were treated for 24, 48 or 72 hours The osmotic potentials of the PEG solutions was 0, -0.3, -0.5, -0.9 and -1.5 MPa including control. The control was not treated with water or PEG. In experiment 3, the seeds were separated into small and large seed and was treated with PEG solution having osmotic potentials of -0.5, -1.1 and -1.8 MPa for 0 (control), 24, and 48 hours. The control was not treated with water or PEG. PEG solution having osmotic potentials (-1.1 and -1.8 MPa) improved germination compared to control (no PEG treatment). Seed treatment durations longer than 48 hours was deleterious and reduced the germination. Seed size has no effect on germination.