The MFLS surveys aimed to collect information on the family formation, fertility, health, and economic well-being of the population in Peninsular Malaysia. Beginning in 1976, the MFLS-1 study included over 1,200 households, each with at least one ever-married woman under the age of 50, across 52 communities in Peninsular Malaysia. Follow-up of participants was conducted across three rounds of data collection, between 1986 and 1987, and each four months apart, with 95% of households participating in all three rounds. MFLS-2 was conducted between 1988 and 1989, the study followed up 72% of the original cohort of MFLS-1 households. Additionally, the MFLS-2 introduced three new samples: adult children of MFLS-1 respondents, over 1,300 older Malaysians aged 50 years or older, and over 2,000 women between 18 to 49 years, regardless of marital status. Over 5,500 participants were assessed in MFLS-2.