A molecular modelling study using the program GRID has been used to investigate the structural requirements of a potential inhibitor binding to Vibrio cholerae sialidase. A number of favourable interactions were predicted between the sialidase and Neu2en derivatives containing hydroxyl- or halogen-substituted acyl groups on the C-5 amine. As a result of this study, a detailed analysis of the interactions of C-5-substituted Neu2en derivatives with the active site of V. cholerae sialidase was undertaken using a conformational searching routine based on molecular dynamics. Based on the results of these molecular design studies several N-acyl-Neu2en-based probes were prepared and evaluated for sialidase inhibition. As envisaged, and pleasingly, the designed compounds were found to be accommodated by the enzyme's active site architecture, and to be strong inhibitors of V. cholerae sialidase.