Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Mounting evidence suggests that many sepsis survivors show long-term neurocognitive deficits in neuropsychological tasks. The underlying mechanisms of these cognitive deficits are not well understood. We utilized psychophysical whole and partial report measures based on the theory of visual attention (TVA) to estimate basic parameters of visual attention and working memory in intensive care-treated survivors of sepsis and sociodemographically matched healthy controls. The study goals were to determine i) whether sepsis survivors show changes in parameters of visual attention and working memory, ii) whether the affected parameters are related to neuropsychological test results in a standard battery, iii) whether between-group differences in these basic parameters of visual attention could account for the underperformance of sepsis survivors in the neuropsychological tests, when adjusting for relevant clinical variables. Results showed a reduction (M = 3.0 for sepsis survivors, M = 3.4 for healthy controls) in working memory capacity parameter K for sepsis survivors. Moreover, K explained variance in neurocognitive outcomes – precisely, attentional and executive functions – in a standard neuropsychological battery. The association remained stable when adjusting for clinical variables, such as anxiety and depression. Thus, a reduction in the number of items to be maintained in a given instant seems to be a critical determinant of the neurocognitive sequelae in sepsis survivors. The working memory storage capacity should be subject of future work on mechanisms but may also serve as surrogate outcome measure in interventions.