Human-animal interactions often have positive physiological and psychological outcomes for humans. The current study extended research in this area by studying three variables that have never directly been examined together within a laboratory setting: task difficulty level (moderate versus extreme), the human-animal interaction (present or absent), and participants' companionanimal guardianship status (yes or no) to determine whether a companion dog would reduce self-reported state anxiety. The participants were undergraduate students from a large western university in the United States who performed timed paper-and-pencil tasks either with or without the presence of a companion dog under varying degrees of task difficulty. Spielberger's State/ Trait anxiety measures were used to assess reactions to the work setting. Results indicated that although the mere presence of a dog is not enough to lower state anxiety for all participants, the interaction of companion-animal guardianship status and task difficulty was significant. Companion animals may assist in stress relief for people in average-stress jobs who already have positive feelings toward companion animals but may have no effect for people in high-stress jobs or who do not already enjoy the company of animals.