Aminolaevulinic acid induced photodynamic therapy (ALA-PDT) is a highly selective way to ablate tissue. A key application of ALA-PDT is in the treatment of non-melanoma skin cancer, in particular basal cell carcinoma (BCC). BCC forms in basal cells deep in the epidermis and is the most common type of non-melanoma skin cancer accounting for approximately 75% of the total. ALA-PDT is a ternary treatment for BCC involving three components: ALA, a pro-drug for the natural photosensitiser protoporphyrin IX (PPIX), light (636 nm) and tissue oxygen. The combination of these, causes cells to be destroyed via the production of reactive oxygen species (ROS) through a necrotic/apoptotic process depending on the PDT conditions employed. These ROS are generated from Type I and II photochemical reactions. The current study investigated the molecular mechanisms of ALA-PDT induced apoptosis in cells (fibroblasts, keratinocytes and squamous carcinoma cells), assessing the amount/type of cell death occurring and also the reactive oxygen species being produced. This is with a view to enhancing treatment protocols. As positive controls in experiments when investigating the effect of ALA-PDT and cell death, fibroblasts were exposed to tumour necrosis factor α (25 ng/ml; TNFα) and hydrogen peroxide (1, 10, 100, 1000 μM). Cells were assessed for type of death by using annexin V binding and fluorescence microscopy after 45 hours. The data showed that there was a statistically significantly increase in % of apoptosis compared to the non-exposed control groups (p<0.05; Student’s t-test and two-way ANOVA, p<0.01 respectively). After setting up a reliable and consistent PDT system, fibroblasts were exposed to 0.5 mM of ALA for 6 hours and thereafter exposed to a red light (630 ± 15 nm; Paterson) for 5 minutes. The cells were assessed for cell death 16 hours after irradiation. The PDT exposed group demonstrated a statistically significant increase in % of apoptosis compared to the non-exposed control group (p<0.01; Student’s t-test). This in vitro cell model will be further employed to explore the effects of pro- and anti-oxidant agents on cell death induced by ALA-PDT.