Barium chlorate can be produced through a double replacement reaction between solutions of barium chloride and sodium chlorate:
:BaCl + 2 NaClO → Ba(ClO) + 2 NaCl
On concentrating and chilling the resulting mixture, barium chlorate precipitates. This is perhaps the most common preparation, exploiting the lower solubility of barium chlorate compared to sodium chlorate.
The above method does result in some sodium contamination, which is undesirable for pyrotechnic purposes, where the strong yellow of sodium can easily overpower the green of barium. Sodium-free barium chlorate can be produced directly through electrolysis:
:BaCl + 6 HO →  Ba(ClO) + 6 H
It can also be produced by the reaction of barium carbonate with boiling ammonium chlorate solution:
:2 NHClO + BaCO + Q → Ba(ClO) + 2 NH + HO + CO
The reaction initially produces barium chlorate and ammonium carbonate; boiling the solution decomposes the ammonium carbonate and drives off the resulting ammonia and carbon dioxide, leaving only barium chlorate in solution.