OBJECTIVE: To compare the costs and effectiveness of early laparoscopy with those of conventional diagnostic methods based on clinical and paraclinical observation and diagnostic images for ascertaining the cause of non-specific acute low abdominal pain (NSALAP) in females of reproductive age from the third-party payers' (TPP) point of view. METHODS: Population: 110 reproductive aged females suffering from NSALAP. Place: Instituto Materno Infantil, perinatal and maternal attention referral hospital in Bogotá, Colombia. Research design: cost-effectiveness study of a controlled clinical trial carried out in 1998 and 1999. Outcomes to be measured: effectiveness, direct medical costs (in Colombian pesos and their equivalent in US dollars (USD-December 2004) from length of hospital stay, diagnostic procedures carried out, medical visits and managing complications. Analysis: Cost-effectiveness incremental ratio, analysing sensitivity in five different scenarios. RESULTS: Early diagnostic laparoscopy was more cost-effective in 4 out of the 5 possible scenarios. Savings varying from $21.875 to $69.834 (USD 9.42 and USD 30.1) were made per unit of increased effectiveness. CONCLUSION: Early diagnostic laparoscopy was cost-effective in 4 out of 5 scenarios dealing with managing NSALAP in reproductive aged females.