BACKGROUND: Electroporation (EP) leverages electric pulses to permeabilize cell membranes, enabling the delivery of therapeutic agents like calcium in cancer treatment. Calcium electroporation (CaEP) induces a rapid influx of calcium ions, disrupting cellular calcium homeostasis and triggering cell death pathways. This study aims to compare the cellular responses between microsecond (µsEP) and nanosecond (nsEP) electroporation, particularly in terms of oxidative stress, immune response activation, and cancer stem cell (CSC) viability in drug-resistant (LoVo Dx) and non-resistant (LoVo) colorectal cancer cell lines. RESULTS: Both µsEP and nsEP, particularly when combined with Ca CONCLUSIONS: The study confirms that nsEP is more effective than µsEP in disrupting cancer cell viability, enhancing oxidative stress, and triggering immune responses, likely through HSP overexpression and ROS generation. nsEP also appears to reduce CSC viability, offering a promising therapeutic approach. However, preserving CD133 expression in the presence of calcium suggests complex interactions that require further investigation. These findings highlight the potential of nsCaEP as an innovative strategy for targeting both cancer cells and CSCs, potentially improving treatment outcomes in colorectal cancer. Further studies are needed to explore the exact cell death mechanisms and optimize protocols for clinical applications.