In the last decade, a new concept of olive orchards based on densities of around 2000 trees/ha arose. Its main advantage is the totally mechanised harvesting that drastically reduces the labour needed to collect the crop. In order to evaluate the suitability of 5 olive cultivars (Arbequina, Arbequina IRTA-i·18, Arbosana, Koroneiki, and Fs-17) to this planting system, a comparative trial was set up in 1999 and the initial results are presented in this study. Koroneiki was the most precocious cultivar, but all the rest bear 3 years after planting. Arbequina and Arbosana had the highest accumulated olive yield 6 years after planting. However, the differences in oil content mitigated the variability in yield. Therefore, accumulated oil yields were not significantly different for all the cultivars under study, except for Fs-17. No significant differences were found between Arbequina and its selected clone Arbequina IRTA-i·18 for any of the traits evaluated. The oleic acid content was low in Arbequina and Fs-17, intermediate in Arbosana, and high in Koroneiki. In conclusion, Arbosana showed a similar suitability to Arbequina for high-density orchards due to its high productivity in the first years after planting and its high oleic acid content. In addition, this cultivar is resistant to Spilocea oleagina and Colletotricum spp. in the area of the trial, Córdoba, southern Spain.