Thioacetic acid is prepared by the reaction of acetic anhydride with hydrogen sulfide:
It has also been produced by the action of phosphorus pentasulfide on glacial acetic acid, followed by distillation.
Thioacetic acid is typically contaminated by acetic acid.
The compound exists exclusively as the thiol tautomer, consistent with the strength of the  double bond. Reflecting the influence of hydrogen-bonding, the boiling point (93 °C) and melting points are 20 and 75 K lower than those for acetic acid.