Prayer is the most common form of religious practice and a central part of religious experience, yet little is known about whether individuals’ prayer activities and beliefs tend to remain stable or develop over the life course. This study examines change during the course of older adulthood in a range of dimensions of prayer, including total frequency of private prayer, specific beliefs and expectancies regarding prayer, and the contents of prayers. Data come from four waves of an ongoing longitudinal survey of Christian older adults, covering a period of seven years. Growth curve analysis was used to model patterns of within-person change in these factors. Linear increase was observed in total prayer frequency and in beliefs about prayer emphasizing placing trust in God over expecting immediate rewards. Frequency of prayer increased for all types of prayer contents, including prayers for others, for God's will, in thanksgiving, for guidance, for health, and for material goods. Only the belief that one's prayers are answered remained stable during the course of the study. Results highlight the dynamic nature of prayer beliefs and behaviors in late life, and partially support a pattern of growing faith maturity.