The bad news follows similarly below-average results in maths, reading and science, released last December.
PISA 2012 is based on a computer-administered assessment of 85,000 students in 44 countries.
2,709 Spanish children in 368 schools participated in the survey.
Spanish students scored 477 points compared to the OECD (Organisation for Economic Co-operation and Development) average of 500 when it came to creatively solving the kind of real-life problems they will face in the workplace.
National daily 20 Minutos reported that 28.5 per cent of Spanish students were found to be incapable of tackling such problems successfully, compared with only 21.4 per cent in most OECD member developed countries.
7.8 per cent of Spanish students were described as 'top performers' compared with 11.4 per cent on average.
To achieve this categorization they had to prove themselves capable of "systematically exploring a complex problem scenario, devising multi-step solutions that take into account all constraints, and adjusting their plans in light of the feedback received."
In Singapore, Korea and Japan more than one in five students achieve this level.
The top-scoring Spaniards were also top-scorers in mathematics, while the OECD noted that the poor performance of "vulnerable" students brought the national average down.
Children of immigrant origin in Spain scored "significantly" worse (39 points) than others but there were no statistical differences between the performances of girls and boys.
Spain came 29th from 44 participating countries, and 23rd in the list of 28 OECD member countries.
Its 477 score was similar to those of Poland (481), Slovakia (483) Slovenia (476), Serbia (473) and Croatia (466), but below Sweden (491), Portugal (494), Germany (509), Italy (510), France (511) and the United Kingdom (517).