Background: The need for adequate nursing resources to the real needs of customers is a key priority for excellence in the quality of nursing care. Hence, it is important to create nursing staff models that assess the impact in nursing care. However there has been no consensus on what variables include, constituting a current concern for managers, in particular with regard the safety in health care. Aim: This research aimed to evaluate the fit of a nursing staff model and their impact on the Nursing Care. Materials And Methods: A quantitative study, transversal and correlational was conducted. Data collection was collected through a questionnaire with three samples: nurses (629), nurses bosses (43) and clients (1290), from 43 hospitals in 8 units with different management models. The psychometric assessment study was conducted through exploratory factor analysis and confirmatory factor analysis who demonstrated adequate validity and reliability for the evaluation of the variables of nursing staff model. Results: The trajectory "Safe Environment → Quality Nursing Care" is statistically significant (BMAS.CESQ = 0.18; SE = 0.08; βMAS.CESQ = 0.15; p = 0.026) so, higher in security work environment, increase the perception of nursing care insurance and quality. Moderate and significant linear correlation (r = 0.49) between the "availability of nurses in adequate quantity" and "availability of nurses with appropriate mix of skills.“ The trajectories "Availability of nurses with appropriate mix of quality nursing skills and care" (BQUAL.CESQ = -0.02, SE = 0.04; βQUAL.CESQ = -0.03; p = 0.663) and "Availability of nurses in adequate quantity and quality of nursing care "(BQUAN.CESQ = 0.04; SE = 0.16; βQUAN.CESQ = -0.02; p = 0.791) did not reveal statistically significant. Discussion and conclusions: The indicators (manifest variables) associated with each of the latent variables from the nursing staff model are relevant to the explanation of the model. The indicators range globally, from moderate relevant to highly relevant. Latent variables presenting β> 0.6. The model reveals acceptable indices of goodness of adjustment, so it is appropriate to explain the relationships between variables. The variables "Availability of nurses with appropriate mix of skills and the adequate quantity” have weak correlations with the perception of "quality nursing care", and the skills of nurses are perceived as less relevant. The Safe Environment is not interdependent on the availability of nurses, yet it is perceived as a very important factor for the promotion of "quality nursing care." The "availability of nurses with the right mix of skills", the "availability of nurses in adequate quantity" and the "safe environment" (Structure variables) explain 2% of the variance of the variables of "quality nursing care" (process variables).