This research is aimed at measuring Family Planning (FP) Behaviour using Long Term Contraceptive Method (LTCM) on FP Practices and Small Happy Prosperous Family Norm (SHPFN) by employing a quantitative approach. The respondents were 1,501 women of Eligible Couple (Elco) aged 15-49 years living in poor, slum, and densely populated areas in Jakarta. The findings show that 62.9% of Elco use modern contraceptives and 39.5% of them use LTCM. All independent variables of FP have a significant linear relationship with FP Behavior with a coefficient of below 0.500 (weak). The influence of behavior on LTCM practice has a coefficient correlation below 0.500, with an exception for LTCM Attitude on LTCM Behavior at 53.3 %. The coefficient correlation of attitude and behavior on the practice of SHPFN is also still low. We recommend greater awareness via information dissemination, education, and communication (IEC) provided to the people and Eligible Couples that modern contraceptive methods including LTCM are safe and comfortable to use. There should also be collaboration between FP providers with health centres, clinics, hospital, and private services providers.