The use of future subjunctive (FS) has suffered a steady decline in written Spanish from the fourteenth century. It is not clear whether it disappeared similarly in each clause, and whether its use was determined by regional distinctions to be considered as a dialectal feature. Granda (1986) suggested that the Hispanic Caribbean countries in the Americas were more conservative in the use of FS in contrast to other regions in a southerly direction. Ramírez-Luengo (2008), however, argued that FS decline occurred uniformly in the Americas, with the eighteenth century being the critical time for the substitution. In a sample of 45 legal documents (60,852 words) from the sixteenth, seventeenth, eighteenth, and nineteenth centuries, issued in northwest and southwest Colombia, the proportions of FS and other alternating forms were equally likely in both regions. FS tabulations were less likely to occur in the nineteenth century within relative clauses, while they were equally likely to occur in conditional protases. This suggests that FS in written Spanish does not show dialectal differences and that its decline might have occurred earlier in relative clauses than conditional protases, probably due to a stylistic motivation.