Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.

How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using the Zacks Mutual Fund Rank, we've found three mutual funds that would be great additions to any long-term investors' portfolios.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

Hartford Schroder Intl Multi Val F (HFYFX): 0.74% expense ratio and 0.7% management fee. HFYFX is a Non US - Equity option, focusing their investments acoss emerging and developed markets, and can often extend across cap levels too. HFYFX has achieved five-year annual returns of an astounding 13.72%.

Lord Abbett Global Eq R3 (LGCRX) is a stand out amongst its peers. LGCRX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations With five-year annualized performance of 11.36%, expense ratio of 1.15% and management fee of 0.45%, this diversified fund is an attractive buy with a strong history of performance.

MFS Blended Research Value Equit R3 (BRULX Quick QuoteBRULX - Free Report) : 0.71% expense ratio and 0.25% management fee. BRULX is a Large Cap Value mutual fund, which invests in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 13.63% over the last five years.

We hope that your investment advisor (if you use one) has you invested in one or all of the top-ranked mutual funds we've reviewed. But if that isn't the case, it might be time to have a conversation or reconsider this vitally important relationship.