Pixel-based analyses are well-established for forensic hydrocarbon fingerprinting. The CHEMSIC (CHEMometric analysis of Selected Ion Chromatograms) method is used in this chapter for analysis of two case studies both with origin in the Persian Gulf region. In contrast to their similar environmental conditions, the studies present different objectives (oil spill identification vs hydrocarbon source differentiation) demanding different strategies concerning e.g., sample collection and compound selection. In case study 1, sediment samples were collected near the Shadegan wetland in Khuzestan province, Iran. Three principal component analysis (PCA) models were constructed using polycyclic aromatic hydrocarbons (PAHs) and petroleum biomarkers in order to differentiate samples according to sources of hydrocarbon pollution and relative concentrations. Results indicate that the petrogenic input in two highly polluted samples is linked to local Iranian sources rather than upstream sources in Iraq. The second case study investigated oil spills from Al Zubarah, Qatar. Four PCA models were constructed using PAHs and petroleum biomarkers, which identified oils from Saudi Arabia and Kuwait as potential sources. It was possible to distinguish samples according to degree of weathering and it indicated that the spill samples originated from crude oil rather than heavy fuel oils.