This article explores the reasons behind the decision by the high clergy and the Crown to advocate a «self-support» policy for the parishes. For those powers, it was more convenient to allow parishes to raise their own revenues instead of finding new sources of income, which could erode tithe collections or put further pressure on the royal treasury, as suggested by some isolated voices during the fourth Mexican provincial council of 1771. However, the predominating trend was to induce the faithful to support their parishes. / El objetivo de este artículo es exponer los motivos del alto clero y de la Corona para reafirmar la política de lo que aquí llamo «auto-sustento» de los curatos. Para esos poderes era más conveniente que cada curato se autofinanciara a tener que buscar nuevas fuentes de ingreso, lo cual podía desembocar en un mayor reparto del diezmo o extraer recursos de la Real Hacienda, como plantearon algunas voces aisladas en el IV Concilio provincial mexicano de 1771. La tendencia fue, por el contrario, garantizar que los fieles sustentaran a cada parroquia.