Dictyostelium discoideum is a unicellular eukaryotic model largely used for the study of the endocytic pathway, mainly due to its high resemblance to the mammalian pathway. Over the last years, Dictyostelium has been increasingly employed for investigating the biogenesis and secretion of secretory lysosomes, given its advantage over mammalian cells. Here we describe protocols for determination of ionic concentration and rates of maturation and exocytosis of these compartments.