Subsistence agriculturalists are highly economically vulnerable, and generally lack access to resources that may help strengthen their livelihoods. Health is a well-established form of human capital that is also one of the biggest assets for subsistence agricultural households. Therefore, any instance in which this form of capital is threatened has potential consequences for livelihood sustainability. This dissertation examined prolonged illness among subsistence agricultural households in rural Mozambique. Prolonged illness can diminish household labor supply, a vital input for subsistence agriculture. My research sought to: 1) identify potential agricultural and land use coping strategies used by unhealthy subsistence agricultural households, and examine whether or not changes in health status induce land cover change; 2) isolate health's effect on a known agricultural land use decision--fallowing--to more rigorously examine the negative health-land relationship; and 3) examine how a policy lever such as access to health services could be more equitably distributed to subsistence agricultural households. I found that unhealthy households were more likely to alter household agricultural land use decisions to cope with prolonged illness, and that they were different than their healthier counterparts in key agricultural ways that may threaten their livelihoods and contribute to food insecurity. While changes in health status do spur land use and land cover change, the relationship is challenging to detect with the current offering of satellite imagery. Additionally, access to health clinics represents a policy lever aimed at supporting unhealthy citizens to maintain their livelihoods. I found that the way "need" is defined in terms of access matters and that access to a high-quality service such as antiretroviral therapy could be more equitably distributed to vulnerable segments of society. This research demonstrates the value of using mixed methods, as the combination of qualitative, econometric, and geospatial methods, to provide a more holistic understanding of the micro-level effects of prolonged illness among subsistence agricultural households in rural Mozambique.