Slum development, growth and attendant challenges of waste generation and management and environmental health challenges are issues for concern in developing countries where waste and environmental management infrastructure are deficit, decaying and moribund. This study aimed to ascertain the slums in Abuja and their characteristics, the actual causes of slum development and growth in Abuja, and the waste generation and management situation in Abuja slums, as well as establish the environmental health challenges arising from waste generation and management in Abuja slums, ascertain government responses to slums development and growth in Abuja, and advocate ways-out and ways-forward. The study adopted field survey, oral interview and laboratory tests of water and soil samples for concentration levels of poisonous metals using the Atomic Absorption Spectroscopy. Principal component analysis of Factor Analysis was used to select significant causes, environmental health challenges, government responses, and ways-out and ways-forward from those suggested by respondents. Findings showed that there were thirty (30) slums in Abuja. The actual causes of slum development were poverty, inequality, inadequate and non-affordable housing for all classes of the citizenry, rural–urban migration, urbanization, poor house planning, poor infrastructure, social exclusion, economic stagnation, informal economy, and labour and work. Waste generation and management situation was unhealthy with poor sanitation practices. Correlation matrix showed significance level above 99% for all indicators. Factor scores showed a perfect correlation above confidence level of 0.05 and very high significance level above 99% in all matrix variables. Open drains and waste dumps characterized Abuja ghettoes and were significant precursors of the outbreak of health devastating diseases in Abuja slums through pollution of air, domestic water sources and soil. Correlation matrix for environmental health challenges showed significance scores above 99% and correlation matrix scores were above 0.5 for all indicators. Water and soil in the slums were highly polluted by toxic metals. Against the World Health Organization (WHO) standard of 0.05 mg/litre for Cd, 0.03 mg/litre for Cr and 0.4 mg/litre for Pb, heavy metal concentration in water sources was too high at 1.1–1.9 mg/litre for Cd, 1.4–1.6.4 mg/litre for Cr and 1.5–1.6 mg/litre for Pb. Heavy metals concentrations in the soil were too high at 4.6–6.2 mg/kg for Cd, 4.9–6.4 mg/kg for Cr and 5.9–6.7 mg/kg for Pb, against the World Health Organization standard of 1.7 mg/kg for Cd, 1.43 mg/kg for Cr and 4.54 mg/kg for Pb. The calculated F value for all the heavy metals was higher than the critical F value of 4.76 at 3 and 6 degrees of freedom with confidence level of 0.05, and the calculated significance level was above 99% in all the variables. Government adopted slums demolition as a solution to unwanted slums development and growth. The study recommended government interventions and initiatives, particularly in poverty reduction; effective implementation of environmental policies, particularly in the area of refuse disposal; slum upgrading programmes and their scaling up as ways-out of the messy slums development and growth and ways-forward.