Inadequate fluid intake contributed to the deaths of 550 patients last year - up 9 per cent on the previous 12 months and up more than 25 per cent on a decade earlier, according to Information Services Division (ISD) Scotland.
The statistics also show 109 patients died malnourished, while 141 died while suffering bedsores.
The figures include people whose malnourishment or dehydration may have been an unavoidable result of their illnesses, meaning not all the cases are due to neglect.
Analysis of the data reveals in 2010, more than ten patients a week were "discharged dead" from hospital with a diagnosis of "volume depletion". The condition is described as the loss of both water and salts and is closely linked to dehydration.
The number of deaths from volume depletion has risen from 429 in 2001 and 503 in 2009. The highest figure in a decade was 638 in 2006.
A further 4,305 people were discharged alive suffering the condition. The British Association for Parenteral and Enteral Nutrition (BAPEN) said not enough was being done to monitor the food and water intake of the frail elderly. BAPEN spokeswoman Rhonda Smith said: "Many hospitals have improved initial screening of patients for malnutrition and dehydration, but in a lot of cases nothing is then happening to monitor their food and fluid intake. It's vital a nutrition and hydration plan is in place for all vulnerable patients and we need people to name and shame hospitals who do not make sure of this."
The Scotland Patients Association described the figures as "utterly horrific".
Chairwoman Margaret Watt said: "These conditions were killing people in Victorian times. It's a disgrace that it's still happening. Nurses shouldn't need reminding to feed and water frail patients and check if they have bedsores."
But she added: "Hospitals are chronically under-staffed and those that are there don't have the time to carry out basic functions. Someone needs to take responsibility for this. More nurses, better training as well as proper checks and balances must be put in place."
Labour health spokeswoman Jackie Baillie said: "We need to ensure that a proper nutrition and hydration plan is in place for all vulnerable patients as it is a disgrace that any patient should suffer in this way and not receive proper care. There is something seriously wrong and nurses themselves have warned older patients are not screened enough for signs of malnutrition and dehydration because of pressures at work."
A Scottish Government spokeswoman said: "Since 2008, we have committed more than 1.75 million to ensure malnutrition screening of all patients, and the funding of 'nutrition champions' in every NHS Board. Also the development of a toolkit to assist all staff dealing with food, fluid and nutrition, from catering staff to senior charge nurses."We have already seen significant improvements in the consideration and delivery of nutritional care with NHS Boards and this remains a high priority."