DescriptionMaintaining a continuous, stable perception of the visual world relies on the ability to integrate information from previous fixations with the current one. An essential component of this integration is transsaccadic memory (TSM), memory for information across saccades. TSM capacity may play a limiting role in tasks requiring efficient transsaccadic integration, such as multiple-fixation visual search tasks. Therefore, we sought to estimate TSM capacity and investigate its relationship to visual short-term memory (VSTM) using two visual search tasks, one where participants maintained fixation while saccades were simulated and another where participants made real saccades. We conducted an ideal observer analysis, which produced lower bound capacity estimates in both tasks that are in line with those previously found for VSTM. These estimates and the results of our ideal observer analysis indicate that TSM capacity may play a limiting role in multiple-fixation visual search tasks.