This diploma thesis deals with information systems for Customer Relationship Management (CRM) and its combination with one of the main recent information technology trends -- Cloud Computing. CRM systems represent fundamental company software. Thanks to Cloud Computing ideas CRM is available now via communication networks as a service with all its relevant benefits and risks. The goal of this thesis is to evaluate CRM provided as a software service, to compare a traditional deployment of CRM as on-premise software with Software-as-a-Service (SaaS), to identify its advantages and disadvantages and finally to offer answers and evaluation of the main Cloud CRM risks. The first part describes CRM background and Cloud Computing principles. The second part compares on-premise and SaaS deployments and evaluates its benefits and risks including a detail cost analysis. The last part deals with Cloud CRM integration possibilities and practical implementation experience including a case study. This thesis offers the answers to bridge the gap between the theoretical and the practical Cloud CRM experience as the main benefit.