Integration of microspheres inside micro-capillaries or hollow waveguides may allow development of compact focusing tools for a variety of biomedical and photonics applications. However, problems associated with developing focusing microprobes involve the multimodal structure of noncollimated beams delivered by fibers and waveguides. By using numerical ray tracing, it is shown that serial spherical microlenses filter out spatially periodic modes which can be used for obtaining tightly focused beams. Experimental studies are performed for spheres with sizes from 10 to 300 μm with different indices of refraction ranging from 1.47 to 1.9. The chains were assembled inside plastic tubing with bore sizes matching the size of the spheres. By using high index spheres, it is demonstrated that these structures are capable of focusing light in contact with tissue. The beam attenuation properties of such chains are found to be in good agreement with numerical modeling results. Potential applications of integrated microsphere arrays include ultra-precise intraocular and neurosurgical laser procedures, photoporation of cells, and coupling of light into photonic microstructures.