Working memory is critical to daily functioning and is a core deficit in numerous disorders. Dopaminergic genes and stress influence working memory, and environmental factors such as stress affect dopamine signaling. Despite this evidence, prior research has not examined the interaction of additive dopaminergic genetic variation and stress to predict working memory. The present study used an augmented dopaminergic additive multilocus genetic profile score (MLPS), and an objective stress-induction, the negative evaluative Trier Social Stress Test, to predict working memory on two complex span tasks (operation span and symmetry span) in N=88 healthy adults. Both tasks were completed twice, once in the context of a non-stressful interview (Session 1), and again in the context of either the negative evaluative Trier Social Stress Test or a non-stressful control protocol (Session 2). We predicted an interaction such that participants with lower MLPSs would benefit from stress whereas those with higher MLPSs would be impaired. Four of the planned variants exhibited sufficient genotyping quality for use in the MLPS. Our results did not support hypotheses and are discussed in relation to experimental design, the coding and conceptualization of the MLPS, and potential genotyping errors. However, we observed low agreement between complex span tasks, and exploratory analyses indicated an MLPS x Stress interaction on operation span performance. Our study aimed to extend a novel additive dopaminergic profile score to working memory capacity and examine the moderating effect of stress. Our results do not support the predicted role of this MLPS, stress, or their interaction.