th The 15 edition of the International Conference on Reliable Software Te- nologies - Ada-Europe 2010-took place in the attractive venue of Valencia, deservedly making Spain the most visited country in the conference series. P- vious editions of the conference were held in Switzerland (Montreux 1996 and Geneva2007),United Kingdom(London1997andYork2005),Sweden(Uppsala 1998),Spain(Santander 1999andPalmade Mallorca2004),Germany(Potsdam 2000), Belgium (Leuven 2001), Austria (Vienna 2002), France (Toulouse 2003 and Brest 2009), Portugal (Porto 2006), and Italy (Venice 2008). Theconferencerepresentsthe mainyearlyeventpromotedbyAda-Europe,in cooperation with ACM SIGAda. This third visit to Spain acknowledges the fact that Ada-Spainisthe largestnationalassociationof Ada-Europe,andis a major contributor to Ada-Europe's activities. This year the conference was organized by members of the Instituto de Automat ' ica e Informa 'tica Industrial (AI2) and the Departamento de Inform' atica de Sistemas y Computadores (DISCA) of the Universidad Polit' ecnica de Valencia. Theyear2010isimportantforAda:thisistheyearwhenthenewamendment to the language (known as Ada 2012) is taking its de?nitive shape. The conf- ence program was not unaware of this fact, and these proceedings re?ect it by including papers about multicore programming in Ada, along with an overview of the key elements of the Ada 2012 amendment in the making. The scienti?c program of the conference, which feeds these proceedings, also included sessions devoted to software dependability, critical, real-time and d- tributed systems, and language technology, all under the more general heading of "Reliable Software Technologies." This program is the result of a thorough selectionprocessof17submissionsoutof42receivedfromauthorsof19di?erent countries.