late cretaceous eggs and eggshell fragments assigned to the oofamily megaloolithidae from salitral de santa rosa (río negro province, northern patagonia, argentina) are studied and compared with other patagonian specimens assigned to the same oofamily. megaloolithids from santa rosa are nearly spherical (mean diameter 10-12 cm) and their eggshell surface is ornamented with hemispheric nodes 0.3-0.8 mm in diameter; pore openings are subcircular to polygonal, and their diameter varies between 0.1 and 0.32 mm. eggshell thickness ranges from 1 to 2.6 mm. the eggshell is composed of fanshaped units that normally display diverging borders and arched accretionary lines. the megaloolithid eggs from santa rosa are associated, at least in some sites of the area, to eggs of different kinds, more usually, thick-shelled faveoloolithids.