Nesting activity of the White-collared Swift (Streptoprocne zonaris) was monitored from October 2001 to March 2002 to describe the breeding chronology of this species. Data were obtained from the colony ‘La Cueva de los Pajaritos’, near Mallín, Córdoba, Argentina. These are the first descriptions of the nesting chronology of this species in Argentina. The breeding season lasted 81 days from egg laying in early November to fledging in middle to late January. Clutch size ranged from one to two eggs which were incubated for an average of 22 days. Nestlings remained in nests for an average of 44 days and fledglings remained at the site for ∼5 additional days. These observations provide new information on nesting sites used by S. zonaris in Argentina, and provide the first documentation of the length of the breeding phases for the species in South America. The ‘apparently shortened’ length of incubation and nestling periods may be a geographical effect, due to this being the most southeastern known breeding colony for S. zonaris.