If the proposition p: There exists an $x \in \mathbb{R}$, such that $x^2+2x+a\leq0$ is a true statement,
then the discriminant $\Delta=4-4a\geq0$,
which implies $a\leq1$,
Therefore, the answer is: $(-\infty, 1]$.
By establishing the inequality relationship based on the equivalent condition of the existential proposition, we can solve the problem.
This question mainly examines the application of the truth of propositions. Converting the truth of the existential proposition into a quadratic inequality is the key to solving this problem.

Thus, the range of values for $a$ is $\boxed{(-\infty, 1]}$.