The growth of e-commerce has the potential to reduce shopping-related travel but brings with it additional freight vehicle trips for the delivery of online orders to consumers. Understanding the overall net effect of e-commerce on urban trip intensity is essential for planning transport infrastructure and services. The paper analyzes how the growth of e-commerce is impacting mobility in Bogotá and Buenos Aires. The demand for e-commerce grew in both cities during the COVID-19 pandemic (2019-21), mostly among higher income groups. Despite the significant potential for replacing private vehicle trips, the analysis finds little evidence that the growth of e-commerce is having a significant substitution effect on shopping trips. Overall, e-commerce currently generates more traffic than it avoids in both Bogotá and Buenos Aires, and, thus, is very likely to continue to add to the road traffic in the two metropolitan areas in the near future.