The precise role of Huntingtin Associated Protein 1 (HAP1) is not known but studies have shown that it is important for early development and survival. A Caenorhabditis elegans (C. elegans) ortholog of HAP1 (T27A3.1 also called trak-1) has been found and is expressed in a subset of neurons. Potential behavioral functions of three knockout lines of T27A3.1 were examined. Based on its suspected role in mice, we hypothesized that T27A3.1 might be involved in egg hatching and early growth, mechanosensation, chemosensation, sensitivity to osmolarity and synaptic transmission. Our studies show that the knockout worms are significantly different from the wildtype worms in only the synaptic transmission test which was measured by adding aldicarb, an acetylcholinesterase inhibitor. The change in function was determined by measuring the number of worms paralyzed. However, when the T27A3.1 worms were tested for egg hatching and early growth, mechanosensation, chemosensation and sensitivity to osmolarity, there were no significant differences between the knockout and wildtype worms.