The overall objective of this work was to assess the suitability of poly(3-octylthiophene) (P3OT) to sustain MC3T3-E1 osteoblast attachment and growth. The central hypothesis was that specific P3OT film properties (i.e., thickness, film preparation conditions, and level of doping) are able to regulate osteoblast functions (i.e., attachment and proliferation). Discrete and combinatorial techniques were utilized to prepare and characterize thin films of P3OT, a semiconductor in its undoped state, and to study its interaction with MC3T3-E1 osteoblasts. In this work we demonstrate that P3OT is a suitable surface to sustain MC3T3-E1 attachment and proliferation with no observed cytotoxicity. We show that P3OT has an effect on MC3T3-E1 attachment and proliferation as area, circularity, and proliferation ratio are significantly different for P3OT compared to control surfaces. We also demonstrate that P3OT doping and film preparation conditions have an effect on osteoblast attachment and proliferation but that thickness over a low and high range does not affect osteoblast functions. This work is significant because it contributes to the growing area of conducting polymers in biomedical applications and establishes P3OT as a potential cell substrate that sustains MC3T3-E1 attachment and promotes high levels of cell proliferation.