New approaches for visualisation of silicon nanoparticles (SiNPs) in cancer cells are realisedby means of the linear and nonlinear optics in vitro. Aqueous colloidal solutions of SiNPs with sizesof about 10–40 nm obtained by ultrasound grinding of silicon nanowires were introduced into breastcancer cells (MCF-7 cell line). Further, the time-varying nanoparticles enclosed in cell structureswere visualised by high-resolution structured illumination microscopy (HR-SIM) and micro-Ramanspectroscopy. Additionally, the nonlinear optical methods of two-photon excited fluorescence (TPEF)and coherent anti-Stokes Raman scattering (CARS) with infrared laser excitation were applied tostudy the localisation of SiNPs in cells. Advantages of the nonlinear methods, such as rapid imaging,which prevents cells from overheating and larger penetration depth compared to the single-photonexcited HR-SIM, are discussed. The obtained results reveal new perspectives of the multimodalvisualisation and precise detection of the uptake of biodegradable non-toxic SiNPs by cancer cellsand they are discussed in view of future applications for the optical diagnostics of cancer tumours.