In an attempt to investigate the putative S-H⋯N hydrogen bond, we have studied the title compound, 1-formyl-3-thiosemicarbazide, which was revealed in a CSD search as a crystal structure which might show such an interaction. However, a redetermination of the structure at room temperature and careful analysis showed that the earlier study [Saxena et al (1991). Acta Cryst. C47, 2374-2376] on which the CSD search was based was in error and that the possibility of an S-H⋯N hydrogen bond is negated. The presence of five other varieties of hydrogen bond (N-H⋯O, N-H⋯S, N-H⋯N, C-H⋯O, C-H⋯S) in the crystal packing prompted us to redirect our efforts and to undertake a study of the charge-density distribution at 90 K. The topological analysis of these five varieties of hydrogen bond was carried out with Bader's quantum theory of 'atoms in molecules' and by applying Koch-Popelier's criteria. The analysis reveals that the hydrogen-bond strength is highest for N-H⋯O and lowest for C-H⋯S with N-H⋯S, N-H⋯N and C-H⋯O forming the middle order. © 2006 International Union of Crystallography Printed in Great Britain - all rights reserved.