In the newly founded town agriculture was important but it was not the main way of making a living: most people were craftsmen and traders. Some trades were organised into guilds, such as the guilds of carpenters, stonemasons, basket weavers, tanners, coopers, weavers and charcoal burners. But the most important of these guilds for the town in socio-economic terms and in terms of politics on the town council were the guilds of ironworkers and blacksmiths.

The crafting of iron gradually developed into an industry, with products no longer being made just for local use but also for export to different areas of Spain, the rest of Europe and even the Americas.

From the late 15th century and on through the 16th and 17th centuries the town of Elorrio was a major manufacturer of edged weapons and firearms. This trade may have had its origins in the earliest days of the local iron working industry.