A comparative analysis of the effect of the starting reagents in the synthesis of YBa2Cu4O8 (124) is presented. Eight different combinations of salts and oxides of the elements in the initial composition were studied. It is shown that all the syntheses starting with;copper nitrate give 124 in approximately 80 h of treatment with only small amounts of CuO and Y2BaCuO5 impurities. Longer times are needed if CuO is used as a starting reagent.