Up until the time of his discovery in Krapina he had worked in different areas of geology, paleontology and minerology. From 1899 to 1905, he led the geological excavations in Krapina and studied in detail the recovered fossil material. A very important part of his studies was a systematic and extremely regular method he used during the exploration of the site itself , which even today makes the understanding of the geological-pantheological relations of the complex easier. He led a precise diary of the excavations, stratisgraphic location of the findings, and made geological profiles and a detailed inventory of the Krapina collection. Also, his ability to recognize the various fragmented parts of the bones and ability to interpret the morphological differences and various changes on the bones themselves. Gorjanović had many discussions concerning the value of the Krapina collection, and he consulted and exchanged opinions with many famous experts worldwide.

He wrote numerous scientific works and led discussions concerning the discovery which made him famous world-wide. In the year 1906 he published his first monography, entitled "Der Diluviale Mensch von Krapina in Kroatien", the most significant work written dealing with the Krapina neanderthal. He recieved a golden medal from the king Franz Joseph I, and the title of the court advisor. H. Virchow, a famous anatomyst of the time, named him "the king of dilluvium".