The casino opened in Portorož half a century after a decision was made to spur tourism development in what was then merely a seaside settlement. At that time, Portorož attracted visitors with health treatments using salt water and mud from the salt pans.

According to a book launched to mark the centenary of gaming in Portorož "Casino Portorož 100 Years", the first casino operated only for a few months. In September 2013, the Austria-Hungarian imperial finance ministry ordered that all gaming parlours in the region be closed.

It took until after World War II to revive the idea of a casino in Portorož. However, gaming was only legal in the former Yugoslavia if organised for charity until an act allowing casinos was passed in 1962.

Casino Portorož, the second casino to open in Yugoslavia, was launched on Christmas Eve 1964 in Hotel Palace, one of the landmarks of Portorož.

However, the casino, which developed to become one of the biggest in Europe, was off limits for Yugoslav citizens and only used foreign currency.

"Casino Portorož 100 Years" describes how former Yugoslavian leader Tito refused to play roulette while visiting the casino in 1973. "As far as I know, gaming is illegal for our citizens," he said when asked whether he would like to play.

A year before Tito's visit, the casino was moved to the then new Metropol hotel, where is has remained until today. The casino flourished under its long-serving director Anton Nino Spinelli, employing up to 450 people.

In the decades under Spinelli, the casino invested much of the profit in public infrastructure in Portorož, especially in the 1970s. Among the biggest casino-funded projects was the reconstruction of a nearby airstrip, which became Slovenia's third international airport.

The casino also funded the construction of open-air auditorium in Portorož and the first marina on the Slovenian coast in the nearby village of Lucija.

However, things started to change for the casino in 1990s. After gaining independence, Slovenia made legislative changes that triggered the development of numerous casinos across the country.

The casino has seen many changes at the helm over the past ten years. The company has also been hit by significant financial problems over the past few years, undergoing two recapitalisations and a court-mandated debt restructuring, and could not avoid layoffs.

The company management is however optimistic about the future, as the process of debt restructuring has been approved in March, a financial restructuring is underway and the company has broken even.